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path: root/drivers/block/xen-blkback/xenbus.c
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2021-04-23xen-blkback: fix compatibility bug with single page ringsPaul Durrant1-22/+16
Prior to commit 4a8c31a1c6f5 ("xen/blkback: rework connect_ring() to avoid inconsistent xenstore 'ring-page-order' set by malicious blkfront"), the behaviour of xen-blkback when connecting to a frontend was: - read 'ring-page-order' - if not present then expect a single page ring specified by 'ring-ref' - else expect a ring specified by 'ring-refX' where X is between 0 and 1 << ring-page-order This was correct behaviour, but was broken by the afforementioned commit to become: - read 'ring-page-order' - if not present then expect a single page ring (i.e. ring-page-order = 0) - expect a ring specified by 'ring-refX' where X is between 0 and 1 << ring-page-order - if that didn't work then see if there's a single page ring specified by 'ring-ref' This incorrect behaviour works most of the time but fails when a frontend that sets 'ring-page-order' is unloaded and replaced by one that does not because, instead of reading 'ring-ref', xen-blkback will read the stale 'ring-ref0' left around by the previous frontend will try to map the wrong grant reference. This patch restores the original behaviour. Fixes: 4a8c31a1c6f5 ("xen/blkback: rework connect_ring() to avoid inconsistent xenstore 'ring-page-order' set by malicious blkfront") Signed-off-by: Paul Durrant <pdurrant@amazon.com> Reviewed-by: Dongli Zhang <dongli.zhang@oracle.com> Reviewed-by: "Roger Pau Monné" <roger.pau@citrix.com> Link: https://lore.kernel.org/r/20210202175659.18452-1-paul@xen.org Signed-off-by: Juergen Gross <jgross@suse.com>
2021-02-12xen/events: link interdomain events to associated xenbus deviceJuergen Gross1-1/+1
In order to support the possibility of per-device event channel settings (e.g. lateeoi spurious event thresholds) add a xenbus device pointer to struct irq_info() and modify the related event channel binding interfaces to take the pointer to the xenbus device as a parameter instead of the domain id of the other side. While at it remove the stale prototype of bind_evtchn_to_irq_lateeoi(). Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Wei Liu <wei.liu@kernel.org> Reviewed-by: Paul Durrant <paul@xen.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-12-14xen-blkback: set ring->xenblkd to NULL after kthread_stop()Pawel Wieczorkiewicz1-0/+1
When xen_blkif_disconnect() is called, the kernel thread behind the block interface is stopped by calling kthread_stop(ring->xenblkd). The ring->xenblkd thread pointer being non-NULL determines if the thread has been already stopped. Normally, the thread's function xen_blkif_schedule() sets the ring->xenblkd to NULL, when the thread's main loop ends. However, when the thread has not been started yet (i.e. wake_up_process() has not been called on it), the xen_blkif_schedule() function would not be called yet. In such case the kthread_stop() call returns -EINTR and the ring->xenblkd remains dangling. When this happens, any consecutive call to xen_blkif_disconnect (for example in frontend_changed() callback) leads to a kernel crash in kthread_stop() (e.g. NULL pointer dereference in exit_creds()). This is XSA-350. Cc: <stable@vger.kernel.org> # 4.12 Fixes: a24fa22ce22a ("xen/blkback: don't use xen_blkif_get() in xen-blkback kthread") Reported-by: Olivier Benjamin <oliben@amazon.com> Reported-by: Pawel Wieczorkiewicz <wipawel@amazon.de> Signed-off-by: Pawel Wieczorkiewicz <wipawel@amazon.de> Reviewed-by: Julien Grall <jgrall@amazon.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2020-12-14xen/xenbus: Add 'will_handle' callback support in xenbus_watch_path()SeongJae Park1-1/+2
Some code does not directly make 'xenbus_watch' object and call 'register_xenbus_watch()' but use 'xenbus_watch_path()' instead. This commit adds support of 'will_handle' callback in the 'xenbus_watch_path()' and it's wrapper, 'xenbus_watch_pathfmt()'. This is part of XSA-349 Cc: stable@vger.kernel.org Signed-off-by: SeongJae Park <sjpark@amazon.de> Reported-by: Michael Kurth <mku@amazon.de> Reported-by: Pawel Wieczorkiewicz <wipawel@amazon.de> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2020-12-09xen: add helpers for caching grant mapping pagesJuergen Gross1-4/+2
Instead of having similar helpers in multiple backend drivers use common helpers for caching pages allocated via gnttab_alloc_pages(). Make use of those helpers in blkback and scsiback. Cc: <stable@vger.kernel.org> # 5.9 Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovksy@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2020-10-21xen-blkback: add a parameter for disabling of persistent grantsSeongJae Park1-6/+16
Persistent grants feature provides high scalability. On some small systems, however, it could incur data copy overheads[1] and thus it is required to be disabled. But, there is no option to disable it. For the reason, this commit adds a module parameter for disabling of the feature. [1] https://wiki.xen.org/wiki/Xen_4.3_Block_Protocol_Scalability Signed-off-by: Anthony Liguori <aliguori@amazon.com> Signed-off-by: SeongJae Park <sjpark@amazon.de> Reviewed-by: Juergen Gross <jgross@suse.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com> Link: https://lore.kernel.org/r/20200923061841.20531-2-sjpark@amazon.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2020-10-20xen/blkback: use lateeoi irq bindingJuergen Gross1-3/+2
In order to reduce the chance for the system becoming unresponsive due to event storms triggered by a misbehaving blkfront use the lateeoi irq binding for blkback and unmask the event channel only after processing all pending requests. As the thread processing requests is used to do purging work in regular intervals an EOI may be sent only after having received an event. If there was no pending I/O request flag the EOI as spurious. This is part of XSA-332. Cc: stable@vger.kernel.org Reported-by: Julien Grall <julien@xen.org> Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Wei Liu <wl@xen.org>
2020-08-24treewide: Use fallthrough pseudo-keywordGustavo A. R. Silva1-1/+1
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-01-29xen/blkback: Consistently insert one empty line between functionsSeongJae Park1-5/+2
The number of empty lines between functions in the xenbus.c is inconsistent. This trivial style cleanup commit fixes the file to consistently place only one empty line. Acked-by: Roger Pau Monné <roger.pau@citrix.com> Signed-off-by: SeongJae Park <sjpark@amazon.de> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2020-01-29xen/blkback: Squeeze page pools if a memory pressure is detectedSeongJae Park1-0/+21
Each `blkif` has a free pages pool for the grant mapping. The size of the pool starts from zero and is increased on demand while processing the I/O requests. If current I/O requests handling is finished or 100 milliseconds has passed since last I/O requests handling, it checks and shrinks the pool to not exceed the size limit, `max_buffer_pages`. Therefore, host administrators can cause memory pressure in blkback by attaching a large number of block devices and inducing I/O. Such problematic situations can be avoided by limiting the maximum number of devices that can be attached, but finding the optimal limit is not so easy. Improper set of the limit can results in memory pressure or a resource underutilization. This commit avoids such problematic situations by squeezing the pools (returns every free page in the pool to the system) for a while (users can set this duration via a module parameter) if memory pressure is detected. Discussions =========== The `blkback`'s original shrinking mechanism returns only pages in the pool which are not currently be used by `blkback` to the system. In other words, the pages that are not mapped with granted pages. Because this commit is changing only the shrink limit but still uses the same freeing mechanism it does not touch pages which are currently mapping grants. Once memory pressure is detected, this commit keeps the squeezing limit for a user-specified time duration. The duration should be neither too long nor too short. If it is too long, the squeezing incurring overhead can reduce the I/O performance. If it is too short, `blkback` will not free enough pages to reduce the memory pressure. This commit sets the value as `10 milliseconds` by default because it is a short time in terms of I/O while it is a long time in terms of memory operations. Also, as the original shrinking mechanism works for at least every 100 milliseconds, this could be a somewhat reasonable choice. I also tested other durations (refer to the below section for more details) and confirmed that 10 milliseconds is the one that works best with the test. That said, the proper duration depends on actual configurations and workloads. That's why this commit allows users to set the duration as a module parameter. Memory Pressure Test ==================== To show how this commit fixes the memory pressure situation well, I configured a test environment on a xen-running virtualization system. On the `blkfront` running guest instances, I attach a large number of network-backed volume devices and induce I/O to those. Meanwhile, I measure the number of pages that swapped in (pswpin) and out (pswpout) on the `blkback` running guest. The test ran twice, once for the `blkback` before this commit and once for that after this commit. As shown below, this commit has dramatically reduced the memory pressure: pswpin pswpout before 76,672 185,799 after 867 3,967 Optimal Aggressive Shrinking Duration ------------------------------------- To find a best squeezing duration, I repeated the test with three different durations (1ms, 10ms, and 100ms). The results are as below: duration pswpin pswpout 1 707 5,095 10 867 3,967 100 362 3,348 As expected, the memory pressure decreases as the duration increases, but the reduction become slow from the `10ms`. Based on this results, I chose the default duration as 10ms. Performance Overhead Test ========================= This commit could incur I/O performance degradation under severe memory pressure because the squeezing will require more page allocations per I/O. To show the overhead, I artificially made a worst-case squeezing situation and measured the I/O performance of a `blkfront` running guest. For the artificial squeezing, I set the `blkback.max_buffer_pages` using the `/sys/module/xen_blkback/parameters/max_buffer_pages` file. In this test, I set the value to `1024` and `0`. The `1024` is the default value. Setting the value as `0` is same to a situation doing the squeezing always (worst-case). If the underlying block device is slow enough, the squeezing overhead could be hidden. For the reason, I use a fast block device, namely the rbd[1]: # xl block-attach guest phy:/dev/ram0 xvdb w For the I/O performance measurement, I run a simple `dd` command 5 times directly to the device as below and collect the 'MB/s' results. $ for i in {1..5}; do dd if=/dev/zero of=/dev/xvdb \ bs=4k count=$((256*512)); sync; done The results are as below. 'max_pgs' represents the value of the `blkback.max_buffer_pages` parameter. max_pgs Min Max Median Avg Stddev 0 417 423 420 419.4 2.5099801 1024 414 425 416 417.8 4.4384682 No difference proven at 95.0% confidence In short, even worst case squeezing on ramdisk based fast block device makes no visible performance degradation. Please note that this is just a very simple and minimal test. On systems using super-fast block devices and a special I/O workload, the results might be different. If you have any doubt, test on your machine with your workload to find the optimal squeezing duration for you. [1] https://www.kernel.org/doc/html/latest/admin-guide/blockdev/ramdisk.html Reviewed-by: Roger Pau Monné <roger.pau@citrix.com> Signed-off-by: SeongJae Park <sjpark@amazon.de> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2019-12-20xen-blkback: support dynamic unbind/bindPaul Durrant1-18/+38
By simply re-attaching to shared rings during connect_ring() rather than assuming they are freshly allocated (i.e assuming the counters are zero) it is possible for vbd instances to be unbound and re-bound from and to (respectively) a running guest. This has been tested by running: while true; do fio --name=randwrite --ioengine=libaio --iodepth=16 \ --rw=randwrite --bs=4k --direct=1 --size=1G --verify=crc32; done in a PV guest whilst running: while true; do echo vbd-$DOMID-$VBD >unbind; echo unbound; sleep 5; echo vbd-$DOMID-$VBD >bind; echo bound; sleep 3; done in dom0 from /sys/bus/xen-backend/drivers/vbd to continuously unbind and re-bind its system disk image. This is a highly useful feature for a backend module as it allows it to be unloaded and re-loaded (i.e. updated) without requiring domUs to be halted. This was also tested by running: while true; do echo vbd-$DOMID-$VBD >unbind; echo unbound; sleep 5; rmmod xen-blkback; echo unloaded; sleep 1; modprobe xen-blkback; echo bound; cd $(pwd); sleep 3; done in dom0 whilst running the same loop as above in the (single) PV guest. Some (less stressful) testing has also been done using a Windows HVM guest with the latest 9.0 PV drivers installed. Signed-off-by: Paul Durrant <pdurrant@amazon.com> Reviewed-by: Juergen Gross <jgross@suse.com> Reviewed-by: Roger Pau Monné <roger.pau@citrix.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2019-12-13xen-blkback: prevent premature module unloadPaul Durrant1-0/+10
Objects allocated by xen_blkif_alloc come from the 'blkif_cache' kmem cache. This cache is destoyed when xen-blkif is unloaded so it is necessary to wait for the deferred free routine used for such objects to complete. This necessity was missed in commit 14855954f636 "xen-blkback: allow module to be cleanly unloaded". This patch fixes the problem by taking/releasing extra module references in xen_blkif_alloc/free() respectively. Signed-off-by: Paul Durrant <pdurrant@amazon.com> Reviewed-by: Roger Pau Monné <roger.pau@citrix.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2019-12-04xen-blkback: allow module to be cleanly unloadedPaul Durrant1-0/+11
Add a module_exit() to perform the necessary clean-up. Signed-off-by: Paul Durrant <pdurrant@amazon.com> Reviewed-by: "Roger Pau Monné" <roger.pau@citrix.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2019-08-12xen/blkback: fix memory leaksWenwen Wang1-3/+3
In read_per_ring_refs(), after 'req' and related memory regions are allocated, xen_blkif_map() is invoked to map the shared frame, irq, and etc. However, if this mapping process fails, no cleanup is performed, leading to memory leaks. To fix this issue, invoke the cleanup before returning the error. Acked-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Wenwen Wang <wenwen@cs.uga.edu> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-30treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157Thomas Gleixner1-9/+1
Based on 3 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version [author] [kishon] [vijay] [abraham] [i] [kishon]@[ti] [com] this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version [author] [graeme] [gregory] [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i] [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema] [hk] [hemahk]@[ti] [com] this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1105 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-24xen/blkback: rework connect_ring() to avoid inconsistent xenstore ↵Dongli Zhang1-29/+43
'ring-page-order' set by malicious blkfront The xenstore 'ring-page-order' is used globally for each blkback queue and therefore should be read from xenstore only once. However, it is obtained in read_per_ring_refs() which might be called multiple times during the initialization of each blkback queue. If the blkfront is malicious and the 'ring-page-order' is set in different value by blkfront every time before blkback reads it, this may end up at the "WARN_ON(i != (XEN_BLKIF_REQS_PER_PAGE * blkif->nr_ring_pages));" in xen_blkif_disconnect() when frontend is destroyed. This patch reworks connect_ring() to read xenstore 'ring-page-order' only once. Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2019-01-17xen/blkback: add stack variable 'blkif' in connect_ring()Dongli Zhang1-13/+14
As 'be->blkif' is used for many times in connect_ring(), the stack variable 'blkif' is added to substitute 'be-blkif'. Suggested-by: Paul Durrant <paul.durrant@citrix.com> Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com> Reviewed-by: Paul Durrant <paul.durrant@citrix.com> Reviewed-by: Roger Pau Monné <roger.pau@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2018-06-13treewide: kzalloc() -> kcalloc()Kees Cook1-1/+2
The kzalloc() function has a 2-factor argument form, kcalloc(). This patch replaces cases of: kzalloc(a * b, gfp) with: kcalloc(a * b, gfp) as well as handling cases of: kzalloc(a * b * c, gfp) with: kzalloc(array3_size(a, b, c), gfp) as it's slightly less ugly than: kzalloc_array(array_size(a, b), c, gfp) This does, however, attempt to ignore constant size factors like: kzalloc(4 * 1024, gfp) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( kzalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | kzalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( kzalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(char) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(u8) * COUNT + COUNT , ...) | kzalloc( - sizeof(__u8) * COUNT + COUNT , ...) | kzalloc( - sizeof(char) * COUNT + COUNT , ...) | kzalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( - kzalloc + kcalloc ( - sizeof(TYPE) * (COUNT_ID) + COUNT_ID, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * COUNT_ID + COUNT_ID, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * (COUNT_CONST) + COUNT_CONST, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * COUNT_CONST + COUNT_CONST, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (COUNT_ID) + COUNT_ID, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * COUNT_ID + COUNT_ID, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (COUNT_CONST) + COUNT_CONST, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * COUNT_CONST + COUNT_CONST, sizeof(THING) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ - kzalloc + kcalloc ( - SIZE * COUNT + COUNT, SIZE , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( kzalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( kzalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kzalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kzalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( kzalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products, // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( kzalloc(C1 * C2 * C3, ...) | kzalloc( - (E1) * E2 * E3 + array3_size(E1, E2, E3) , ...) | kzalloc( - (E1) * (E2) * E3 + array3_size(E1, E2, E3) , ...) | kzalloc( - (E1) * (E2) * (E3) + array3_size(E1, E2, E3) , ...) | kzalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants, // keeping sizeof() as the second factor argument. @@ expression THING, E1, E2; type TYPE; constant C1, C2, C3; @@ ( kzalloc(sizeof(THING) * C2, ...) | kzalloc(sizeof(TYPE) * C2, ...) | kzalloc(C1 * C2 * C3, ...) | kzalloc(C1 * C2, ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * (E2) + E2, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * E2 + E2, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (E2) + E2, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * E2 + E2, sizeof(THING) , ...) | - kzalloc + kcalloc ( - (E1) * E2 + E1, E2 , ...) | - kzalloc + kcalloc ( - (E1) * (E2) + E1, E2 , ...) | - kzalloc + kcalloc ( - E1 * E2 + E1, E2 , ...) ) Signed-off-by: Kees Cook <keescook@chromium.org>
2018-05-24block drivers/block: Use octal not symbolic permissionsJoe Perches1-2/+2
Convert the S_<FOO> symbolic permissions to their octal equivalents as using octal and not symbolic permissions is preferred by many as more readable. see: https://lkml.org/lkml/2016/8/2/1945 Done with automated conversion via: $ ./scripts/checkpatch.pl -f --types=SYMBOLIC_PERMS --fix-inplace <files...> Miscellanea: o Wrapped modified multi-line calls to a single line where appropriate o Realign modified multi-line calls to open parenthesis Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-09-07Merge branch 'for-4.14/block' of git://git.kernel.dk/linux-blockLinus Torvalds1-1/+2
Pull block layer updates from Jens Axboe: "This is the first pull request for 4.14, containing most of the code changes. It's a quiet series this round, which I think we needed after the churn of the last few series. This contains: - Fix for a registration race in loop, from Anton Volkov. - Overflow complaint fix from Arnd for DAC960. - Series of drbd changes from the usual suspects. - Conversion of the stec/skd driver to blk-mq. From Bart. - A few BFQ improvements/fixes from Paolo. - CFQ improvement from Ritesh, allowing idling for group idle. - A few fixes found by Dan's smatch, courtesy of Dan. - A warning fixup for a race between changing the IO scheduler and device remova. From David Jeffery. - A few nbd fixes from Josef. - Support for cgroup info in blktrace, from Shaohua. - Also from Shaohua, new features in the null_blk driver to allow it to actually hold data, among other things. - Various corner cases and error handling fixes from Weiping Zhang. - Improvements to the IO stats tracking for blk-mq from me. Can drastically improve performance for fast devices and/or big machines. - Series from Christoph removing bi_bdev as being needed for IO submission, in preparation for nvme multipathing code. - Series from Bart, including various cleanups and fixes for switch fall through case complaints" * 'for-4.14/block' of git://git.kernel.dk/linux-block: (162 commits) kernfs: checking for IS_ERR() instead of NULL drbd: remove BIOSET_NEED_RESCUER flag from drbd_{md_,}io_bio_set drbd: Fix allyesconfig build, fix recent commit drbd: switch from kmalloc() to kmalloc_array() drbd: abort drbd_start_resync if there is no connection drbd: move global variables to drbd namespace and make some static drbd: rename "usermode_helper" to "drbd_usermode_helper" drbd: fix race between handshake and admin disconnect/down drbd: fix potential deadlock when trying to detach during handshake drbd: A single dot should be put into a sequence. drbd: fix rmmod cleanup, remove _all_ debugfs entries drbd: Use setup_timer() instead of init_timer() to simplify the code. drbd: fix potential get_ldev/put_ldev refcount imbalance during attach drbd: new disk-option disable-write-same drbd: Fix resource role for newly created resources in events2 drbd: mark symbols static where possible drbd: Send P_NEG_ACK upon write error in protocol != C drbd: add explicit plugging when submitting batches drbd: change list_for_each_safe to while(list_first_entry_or_null) drbd: introduce drbd_recv_header_maybe_unplug ...
2017-08-25xen-blkback: stop blkback thread of every queue in xen_blkif_disconnectAnnie Li1-2/+8
In xen_blkif_disconnect, before checking inflight I/O, following code stops the blkback thread, if (ring->xenblkd) { kthread_stop(ring->xenblkd); wake_up(&ring->shutdown_wq); } If there is inflight I/O in any non-last queue, blkback returns -EBUSY directly, and above code would not be called to stop thread of remaining queue and processs them. When removing vbd device with lots of disk I/O load, some queues with inflight I/O still have blkback thread running even though the corresponding vbd device or guest is gone. And this could cause some problems, for example, if the backend device type is file, some loop devices and blkback thread always lingers there forever after guest is destroyed, and this causes failure of umounting repositories unless rebooting the dom0. This patch allows thread of every queue has the chance to get stopped. Otherwise, only thread of queue previous to(including) first busy one get stopped, blkthread of remaining queue will still run. So stop all threads properly and return -EBUSY if any queue has inflight I/O. Signed-off-by: Annie Li <annie.li@oracle.com> Reviewed-by: Herbert van den Bergh <herbert.van.den.bergh@oracle.com> Reviewed-by: Bhavesh Davda <bhavesh.davda@oracle.com> Reviewed-by: Adnan Misherfi <adnan.misherfi@oracle.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2017-08-18xen-blkback: Avoid that gcc 7 warns about fall-through when building with W=1Bart Van Assche1-1/+2
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Roger Pau Monn303251 <roger.pau@citrix.com> Cc: xen-devel@lists.xenproject.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-13xen/blkback: don't use xen_blkif_get() in xen-blkback kthreadJuergen Gross1-1/+0
There is no need to use xen_blkif_get()/xen_blkif_put() in the kthread of xen-blkback. Thread stopping is synchronous and using the blkif reference counting in the kthread will avoid to ever let the reference count drop to zero at the end of an I/O running concurrent to disconnecting and multiple rings. Setting ring->xenblkd to NULL after stopping the kthread isn't needed as the kthread does this already. Signed-off-by: Juergen Gross <jgross@suse.com> Tested-by: Steven Haigh <netwiz@crc.id.au> Acked-by: Roger Pau Monné <roger.pau@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2017-06-13xen/blkback: don't free be structure too earlyJuergen Gross1-4/+3
The be structure must not be freed when freeing the blkif structure isn't done. Otherwise a use-after-free of be when unmapping the ring used for communicating with the frontend will occur in case of a late call of xenblk_disconnect() (e.g. due to an I/O still active when trying to disconnect). Signed-off-by: Juergen Gross <jgross@suse.com> Tested-by: Steven Haigh <netwiz@crc.id.au> Acked-by: Roger Pau Monné <roger.pau@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2017-06-13xen/blkback: fix disconnect while I/Os in flightJuergen Gross1-2/+5
Today disconnecting xen-blkback is broken in case there are still I/Os in flight: xen_blkif_disconnect() will bail out early without releasing all resources in the hope it will be called again when the last request has terminated. This, however, won't happen as xen_blkif_free() won't be called on termination of the last running request: xen_blkif_put() won't decrement the blkif refcnt to 0 as xen_blkif_disconnect() didn't finish before thus some xen_blkif_put() calls in xen_blkif_disconnect() didn't happen. To solve this deadlock xen_blkif_disconnect() and xen_blkif_alloc_rings() shouldn't use xen_blkif_put() and xen_blkif_get() but use some other way to do their accounting of resources. This at once fixes another error in xen_blkif_disconnect(): when it returned early with -EBUSY for another ring than 0 it would call xen_blkif_put() again for already handled rings on a subsequent call. This will lead to inconsistencies in the refcnt handling. Cc: stable@vger.kernel.org Signed-off-by: Juergen Gross <jgross@suse.com> Tested-by: Steven Haigh <netwiz@crc.id.au> Acked-by: Roger Pau Monné <roger.pau@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2017-05-16block: xen-blkback: add null check to avoid null pointer dereferenceGustavo A. R. Silva1-3/+5
Add null check before calling xen_blkif_put() to avoid potential null pointer dereference. Addresses-Coverity-ID: 1350942 Cc: Juergen Gross <jgross@suse.com> Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2017-02-09xen: modify xenstore watch event interfaceJuergen Gross1-3/+3
Today a Xenstore watch event is delivered via a callback function declared as: void (*callback)(struct xenbus_watch *, const char **vec, unsigned int len); As all watch events only ever come with two parameters (path and token) changing the prototype to: void (*callback)(struct xenbus_watch *, const char *path, const char *token); is the natural thing to do. Apply this change and adapt all users. Cc: konrad.wilk@oracle.com Cc: roger.pau@citrix.com Cc: wei.liu2@citrix.com Cc: paul.durrant@citrix.com Cc: netdev@vger.kernel.org Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Paul Durrant <paul.durrant@citrix.com> Reviewed-by: Wei Liu <wei.liu2@citrix.com> Reviewed-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2016-11-07xen: make use of xenbus_read_unsigned() in xen-blkbackJuergen Gross1-22/+14
Use xenbus_read_unsigned() instead of xenbus_scanf() when possible. This requires to change the type of one read from int to unsigned, but this case has been wrong before: negative values are not allowed for the modified case. Cc: konrad.wilk@oracle.com Cc: roger.pau@citrix.com Signed-off-by: Juergen Gross <jgross@suse.com> Acked-by: David Vrabel <david.vrabel@citrix.com>
2016-07-27Merge tag 'for-linus-4.8-rc0-tag' of ↵Linus Torvalds1-9/+11
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull xen updates from David Vrabel: "Features and fixes for 4.8-rc0: - ACPI support for guests on ARM platforms. - Generic steal time support for arm and x86. - Support cases where kernel cpu is not Xen VCPU number (e.g., if in-guest kexec is used). - Use the system workqueue instead of a custom workqueue in various places" * tag 'for-linus-4.8-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (47 commits) xen: add static initialization of steal_clock op to xen_time_ops xen/pvhvm: run xen_vcpu_setup() for the boot CPU xen/evtchn: use xen_vcpu_id mapping xen/events: fifo: use xen_vcpu_id mapping xen/events: use xen_vcpu_id mapping in events_base x86/xen: use xen_vcpu_id mapping when pointing vcpu_info to shared_info x86/xen: use xen_vcpu_id mapping for HYPERVISOR_vcpu_op xen: introduce xen_vcpu_id mapping x86/acpi: store ACPI ids from MADT for future usage x86/xen: update cpuid.h from Xen-4.7 xen/evtchn: add IOCTL_EVTCHN_RESTRICT xen-blkback: really don't leak mode property xen-blkback: constify instance of "struct attribute_group" xen-blkfront: prefer xenbus_scanf() over xenbus_gather() xen-blkback: prefer xenbus_scanf() over xenbus_gather() xen: support runqueue steal time on xen arm/xen: add support for vm_assist hypercall xen: update xen headers xen-pciback: drop superfluous variables xen-pciback: short-circuit read path used for merging write values ...
2016-07-22xen-blkback: really don't leak mode propertyJan Beulich1-1/+4
Commit 9d092603cc ("xen-blkback: do not leak mode property") left one path unfixed; correct this. Acked-by: Jens Axboe <axboe@kernel.dk> Acked-by: Roger Pau Monné <roger.pau@citrix.com> Signed-off-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2016-07-22xen-blkback: constify instance of "struct attribute_group"Jan Beulich1-1/+1
The functions these get passed to have been taking pointers to const since at least 2.6.16. Acked-by: Jens Axboe <axboe@kernel.dk> Acked-by: Roger Pau Monné <roger.pau@citrix.com> Signed-off-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2016-07-22xen-blkback: prefer xenbus_scanf() over xenbus_gather()Jan Beulich1-7/+6
... for single items being collected: It is more typesafe (as the compiler can check format string and to-be-written-to variable match) and requires one less parameter to be passed. Signed-off-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com> Acked-by: Jens Axboe <axboe@kernel.dk>
2016-06-09block: add a separate operation type for secure eraseChristoph Hellwig1-1/+1
Instead of overloading the discard support with the REQ_SECURE flag. Use the opportunity to rename the queue flag as well, and remove the dead checks for this flag in the RAID 1 and RAID 10 drivers that don't claim support for secure erase. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2016-04-13block: kill off q->flush_flagsJens Axboe1-1/+1
Now that we converted everything to the newer block write cache interface, kill off the queue flush_flags and queueable flush entries. Signed-off-by: Jens Axboe <axboe@fb.com>
2016-03-04xen/blback: Fit the important information of the thread in 17 charactersKonrad Rzeszutek Wilk1-4/+3
The processes names are truncated to 17, while we had the length of the process as name 20 - which meant that while we filled it out with various details - the last 3 characters (which had the queue number) never surfaced to the user-space. To simplify this and be able to fit the device name, domain id, and the queue number we remove the 'blkback' from the name. Prior to this patch the device name is "blkback.<domid>.<name>" for example: blkback.8.xvda, blkback.11.hda. With the multiqueue block backend we add "-%d" for the queue. But sadly this is already way past the limit so it gets stripped. Possible solution had been identified by Ian: http://lists.xenproject.org/archives/html/xen-devel/2015-05/msg03516.html " If you are pressed for space then the "xvd" is probably a bit redundant in a string which starts blkbk. The guest may not even call the device xvdN (iirc BSD has another prefix) any how, so having blkback say so seems of limited use anyway. Since this seems to not include a partition number how does this work in the split partition scheme? (i.e. one where the guest is given xvda1 and xvda2 rather than xvda with a partition table) [It will be 'blkback.8.xvda1', and 'blkback.11.xvda2'] Perhaps something derived from one of the schemes in http://xenbits.xen.org/docs/unstable/misc/vbd-interface.txt might be a better fit? After a bit of discussion (see http://lists.xenproject.org/archives/html/xen-devel/2015-12/msg01588.html) we settled on dropping the "blback" part. This will make it possible to have the <domid>.<name>-<queue>: [1.xvda-0] [1.xvda-1] And we enough space to make it go up to: [32100.xvdfg9-5] Acked-by: Roger Pau Monné <roger.pau@citrix.com> Reported-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2016-03-04xen-blkback: advertise indirect segment support earlierJan Beulich1-5/+8
There's no reason to defer this until the connect phase, and in fact there are frontend implementations expecting this to be available earlier. Move it into the probe function. Acked-by: Roger Pau Monné <roger.pau@citrix.com> Signed-off-by: Jan Beulich <jbeulich@suse.com> Cc: Bob Liu <bob.liu@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2016-01-04xen/blkback: Fix two memory leaks.Bob Liu1-6/+11
This patch fixs two memleaks: backtrace: [<ffffffff817ba5e8>] kmemleak_alloc+0x28/0x50 [<ffffffff81205e3b>] kmem_cache_alloc+0xbb/0x1d0 [<ffffffff81534028>] xen_blkbk_probe+0x58/0x230 [<ffffffff8146adb6>] xenbus_dev_probe+0x76/0x130 [<ffffffff81511716>] driver_probe_device+0x166/0x2c0 [<ffffffff815119bc>] __device_attach_driver+0xac/0xb0 [<ffffffff8150fa57>] bus_for_each_drv+0x67/0x90 [<ffffffff81511ab7>] __device_attach+0xc7/0x120 [<ffffffff81511b23>] device_initial_probe+0x13/0x20 [<ffffffff8151059a>] bus_probe_device+0x9a/0xb0 [<ffffffff8150f0a1>] device_add+0x3b1/0x5c0 [<ffffffff8150f47e>] device_register+0x1e/0x30 [<ffffffff8146a9e8>] xenbus_probe_node+0x158/0x170 [<ffffffff8146abaf>] xenbus_dev_changed+0x1af/0x1c0 [<ffffffff8146b1bb>] backend_changed+0x1b/0x20 [<ffffffff81468ca6>] xenwatch_thread+0xb6/0x160 unreferenced object 0xffff880007ba8ef8 (size 224): backtrace: [<ffffffff817ba5e8>] kmemleak_alloc+0x28/0x50 [<ffffffff81205c73>] __kmalloc+0xd3/0x1e0 [<ffffffff81534d87>] frontend_changed+0x2c7/0x580 [<ffffffff8146af12>] xenbus_otherend_changed+0xa2/0xb0 [<ffffffff8146b2c0>] frontend_changed+0x10/0x20 [<ffffffff81468ca6>] xenwatch_thread+0xb6/0x160 [<ffffffff810d3e97>] kthread+0xd7/0xf0 [<ffffffff817c4a9f>] ret_from_fork+0x3f/0x70 [<ffffffffffffffff>] 0xffffffffffffffff unreferenced object 0xffff8800048dcd38 (size 224): The first leak is caused by not put() the be->blkif reference which we had gotten in xen_blkif_alloc(), while the second is us not freeing blkif->rings in the right place. Signed-off-by: Bob Liu <bob.liu@oracle.com> Reported-and-Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2016-01-04xen/blkback: make st_ statistics per ringBob Liu1-10/+35
Make st_* statistics per ring and the VBD sysfs would iterate over all the rings. Note: xenvbd_sysfs_delif() is called in xen_blkbk_remove() before all rings are torn down, so it's safe. Signed-off-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> --- v2: Aligned the variables on the same column.
2016-01-04xen/blkback: Free resources if connect_ring failed.Konrad Rzeszutek Wilk1-1/+7
With the multi-queue support we could fail at setting up some of the rings and fail the connection. That meant that all resources tied to rings[0..n-1] (where n is the ring that failed to be setup). Eventually the frontend will switch to the states and we will call xen_blkif_disconnect. However we do not want to be at the mercy of the frontend deciding when to change states. This allows us to do the cleanup right away and freeing resources. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2016-01-04xen/blocks: Return -EXX instead of -1Konrad Rzeszutek Wilk1-1/+1
Lets return sensible values instead of -1. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2016-01-04xen/blkback: make pool of persistent grants and free pages per-queueBob Liu1-11/+10
Make pool of persistent grants and free pages per-queue/ring instead of per-device to get better scalability. Test was done based on null_blk driver: dom0: v4.2-rc8 16vcpus 10GB "modprobe null_blk" domu: v4.2-rc8 16vcpus 10GB [test] rw=read direct=1 ioengine=libaio bs=4k time_based runtime=30 filename=/dev/xvdb numjobs=16 iodepth=64 iodepth_batch=64 iodepth_batch_complete=64 group_reporting Results: iops1: After patch "xen/blkfront: make persistent grants per-queue". iops2: After this patch. Queues: 1 4 8 16 Iops orig(k): 810 1064 780 700 Iops1(k): 810 1230(~20%) 1024(~20%) 850(~20%) Iops2(k): 810 1410(~35%) 1354(~75%) 1440(~100%) With 4 queues after this commit we can get ~75% increase in IOPS, and performance won't drop if increasing queue numbers. Please find the respective chart in this link: https://www.dropbox.com/s/agrcy2pbzbsvmwv/iops.png?dl=0 Signed-off-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2016-01-04xen/blkback: get the number of hardware queues/rings from blkfrontBob Liu1-6/+28
Backend advertises "multi-queue-max-queues" to front, also get the negotiated number from "multi-queue-num-queues" written by blkfront. Signed-off-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2016-01-04xen/blkback: pseudo support for multi hardware queues/ringsKonrad Rzeszutek Wilk1-104/+173
Preparatory patch for multiple hardware queues (rings). The number of rings is unconditionally set to 1, larger number will be enabled in "xen/blkback: get the number of hardware queues/rings from blkfront". Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com> Signed-off-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> --- v2: Align variables in the structures.
2016-01-04xen/blkback: separate ring information out of struct xen_blkifBob Liu1-47/+49
Split per ring information to an new structure "xen_blkif_ring", so that one vbd device can be associated with one or more rings/hardware queues. Introduce 'pers_gnts_lock' to protect the pool of persistent grants since we may have multi backend threads. This patch is a preparation for supporting multi hardware queues/rings. Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com> Signed-off-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> --- v2: Align the variables in the structure.
2015-10-23xen/xenbus: Rename *RING_PAGE* to *RING_GRANT*Julien Grall1-1/+1
Linux may use a different page size than the size of grant. So make clear that the order is actually in number of grant. Signed-off-by: Julien Grall <julien.grall@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-10-23block/xen-blkback: Make it running on 64KB page granularityJulien Grall1-3/+6
The PV block protocol is using 4KB page granularity. The goal of this patch is to allow a Linux using 64KB page granularity behaving as a block backend on a non-modified Xen. It's only necessary to adapt the ring size and the number of request per indirect frames. The rest of the code is relying on the grant table code. Note that the grant table code is allocating a Linux page per grant which will result to waste 6OKB for every grant when Linux is using 64KB page granularity. This could be improved by sharing the page between multiple grants. Signed-off-by: Julien Grall <julien.grall@citrix.com> Acked-by: "Roger Pau Monné" <roger.pau@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-09-23xen/blkback: free requests on disconnectionRoger Pau Monne1-18/+20
This is due to commit 86839c56dee28c315a4c19b7bfee450ccd84cd25 "xen/block: add multi-page ring support" When using an guest under UEFI - after the domain is destroyed the following warning comes from blkback. ------------[ cut here ]------------ WARNING: CPU: 2 PID: 95 at /home/julien/works/linux/drivers/block/xen-blkback/xenbus.c:274 xen_blkif_deferred_free+0x1f4/0x1f8() Modules linked in: CPU: 2 PID: 95 Comm: kworker/2:1 Tainted: G W 4.2.0 #85 Hardware name: APM X-Gene Mustang board (DT) Workqueue: events xen_blkif_deferred_free Call trace: [<ffff8000000890a8>] dump_backtrace+0x0/0x124 [<ffff8000000891dc>] show_stack+0x10/0x1c [<ffff8000007653bc>] dump_stack+0x78/0x98 [<ffff800000097e88>] warn_slowpath_common+0x9c/0xd4 [<ffff800000097f80>] warn_slowpath_null+0x14/0x20 [<ffff800000557a0c>] xen_blkif_deferred_free+0x1f0/0x1f8 [<ffff8000000ad020>] process_one_work+0x160/0x3b4 [<ffff8000000ad3b4>] worker_thread+0x140/0x494 [<ffff8000000b2e34>] kthread+0xd8/0xf0 ---[ end trace 6f859b7883c88cdd ]--- Request allocation has been moved to connect_ring, which is called every time blkback connects to the frontend (this can happen multiple times during a blkback instance life cycle). On the other hand, request freeing has not been moved, so it's only called when destroying the backend instance. Due to this mismatch, blkback can allocate the request pool multiple times, without freeing it. In order to fix it, move the freeing of requests to xen_blkif_disconnect to restore the symmetry between request allocation and freeing. Reported-by: Julien Grall <julien.grall@citrix.com> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Tested-by: Julien Grall <julien.grall@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: xen-devel@lists.xenproject.org CC: stable@vger.kernel.org # 4.2 Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2015-06-06xen/block: add multi-page ring supportBob Liu1-20/+69
Extend xen/block to support multi-page ring, so that more requests can be issued by using more than one pages as the request ring between blkfront and backend. As a result, the performance can get improved significantly. We got some impressive improvements on our highend iscsi storage cluster backend. If using 64 pages as the ring, the IOPS increased about 15 times for the throughput testing and above doubled for the latency testing. The reason was the limit on outstanding requests is 32 if use only one-page ring, but in our case the iscsi lun was spread across about 100 physical drives, 32 was really not enough to keep them busy. Changes in v2: - Rebased to 4.0-rc6. - Document on how multi-page ring feature working to linux io/blkif.h. Changes in v3: - Remove changes to linux io/blkif.h and follow the protocol defined in io/blkif.h of XEN tree. - Rebased to 4.1-rc3 Changes in v4: - Turn to use 'ring-page-order' and 'max-ring-page-order'. - A few comments from Roger. Changes in v5: - Clarify with 4k granularity to comment - Address more comments from Roger Signed-off-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2015-06-06drivers: xen-blkback: delay pending_req allocation to connect_ringBob Liu1-44/+38
This is a pre-patch for multi-page ring feature. In connect_ring, we can know exactly how many pages are used for the shared ring, delay pending_req allocation here so that we won't waste too much memory. Signed-off-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2015-04-17Merge branch 'for-4.1/drivers' of git://git.kernel.dk/linux-blockLinus Torvalds1-15/+23
Pull block driver updates from Jens Axboe: "This is the block driver pull request for 4.1. As with the core bits, this is a relatively slow round. This pull request contains: - Various fixes and cleanups for NVMe, from Alexey Khoroshilov, Chong Yuan, myself, Keith Busch, and Murali Iyer. - Documentation and code cleanups for nbd from Markus Pargmann. - Change of brd maintainer to me, from Ross Zwisler. At least the email doesn't bounce anymore then. - Two xen-blkback fixes from Tao Chen" * 'for-4.1/drivers' of git://git.kernel.dk/linux-block: (23 commits) NVMe: Meta data handling through submit io ioctl NVMe: Add translation for block limits NVMe: Remove check for null NVMe: Fix error handling of class_create("nvme") xen-blkback: define pr_fmt macro to avoid the duplication of DRV_PFX xen-blkback: enlarge the array size of blkback name nbd: Return error pointer directly nbd: Return error code directly nbd: Remove fixme that was already fixed nbd: Restructure debugging prints nbd: Fix device bytesize type nbd: Replace kthread_create with kthread_run nbd: Remove kernel internal header Documentation: nbd: Add list of module parameters Documentation: nbd: Reformat to allow more documentation NVMe: increase depth of admin queue nvme: Fix PRP list calculation for non-4k system page size NVMe: Fix blk-mq hot cpu notification NVMe: embedded iod mask cleanup NVMe: Freeze admin queue on device failure ...
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