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2021-07-279p/xen: Fix end of loop tests for list_for_each_entryHarshvardhan Jha1-2/+2
This patch addresses the following problems: - priv can never be NULL, so this part of the check is useless - if the loop ran through the whole list, priv->client is invalid and it is more appropriate and sufficient to check for the end of list_for_each_entry loop condition. Link: http://lkml.kernel.org/r/20210727000709.225032-1-harshvardhan.jha@oracle.com Signed-off-by: Harshvardhan Jha <harshvardhan.jha@oracle.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Tested-by: Stefano Stabellini <sstabellini@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2020-10-099p/xen: Fix format argument warningYe Bin1-2/+2
Fix follow warnings: [net/9p/trans_xen.c:454]: (warning) %u in format string (no. 1) requires 'unsigned int' but the argument type is 'int'. [net/9p/trans_xen.c:460]: (warning) %u in format string (no. 1) requires 'unsigned int' but the argument type is 'int'. Link: http://lkml.kernel.org/r/20201009080552.89918-1-yebin10@huawei.com Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Ye Bin <yebin10@huawei.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.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>
2020-06-029p/xen: increase XEN_9PFS_RING_ORDERStefano Stabellini1-27/+34
Increase XEN_9PFS_RING_ORDER to 9 for performance reason. Order 9 is the max allowed by the protocol. We can't assume that all backends will support order 9. The xenstore property max-ring-page-order specifies the max order supported by the backend. We'll use max-ring-page-order for the size of the ring. This means that the size of the ring is not static (XEN_FLEX_RING_SIZE(9)) anymore. Change XEN_9PFS_RING_SIZE to take an argument and base the calculation on the order chosen at setup time. Finally, modify p9_xen_trans.maxsize to be divided by 4 compared to the original value. We need to divide it by 2 because we have two rings coming off the same order allocation: the in and out rings. This was a mistake in the original code. Also divide it further by 2 because we don't want a single request/reply to fill up the entire ring. There can be multiple requests/replies outstanding at any given time and if we use the full ring with one, we risk forcing the backend to wait for the client to read back more replies before continuing, which is not performant. Link: http://lkml.kernel.org/r/20200521193242.15953-1-sstabellini@kernel.org Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com> Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2019-07-13Merge tag '9p-for-5.3' of git://github.com/martinetd/linuxLinus Torvalds1-1/+7
Pull 9p updates from Dominique Martinet: "Two small fixes to properly cleanup the 9p transports list if virtio/xen module initialization fail. 9p might otherwise try to access memory from a module that failed to register got freed" * tag '9p-for-5.3' of git://github.com/martinetd/linux: 9p/xen: Add cleanup path in p9_trans_xen_init 9p/virtio: Add cleanup path in p9_virtio_init
2019-05-159p/xen: Add cleanup path in p9_trans_xen_initYueHaibing1-1/+7
If xenbus_register_frontend() fails in p9_trans_xen_init, we should call v9fs_unregister_trans() to do cleanup. Link: http://lkml.kernel.org/r/20190430143933.19368-1-yuehaibing@huawei.com Cc: stable@vger.kernel.org Fixes: 868eb122739a ("xen/9pfs: introduce Xen 9pfs transport driver") Signed-off-by: YueHaibing <yuehaibing@huawei.com> Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2019-01-239p: mark expected switch fall-throughGustavo A. R. Silva1-1/+1
In preparation to enabling -Wimplicit-fallthrough, mark switch cases where we are expecting to fall through. This patch fixes the following warning: net/9p/trans_xen.c:514:6: warning: this statement may fall through [-Wimplicit-fallthrough=] Warning level 3 was used: -Wimplicit-fallthrough=3 This patch is part of the ongoing efforts to enabling -Wimplicit-fallthrough Link: http://lkml.kernel.org/r/20190123071632.GA8039@embeddedor Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2018-09-079p: Add refcount to p9_req_tTomas Bortoli1-0/+1
To avoid use-after-free(s), use a refcount to keep track of the usable references to any instantiated struct p9_req_t. This commit adds p9_req_put(), p9_req_get() and p9_req_try_get() as wrappers to kref_put(), kref_get() and kref_get_unless_zero(). These are used by the client and the transports to keep track of valid requests' references. p9_free_req() is added back and used as callback by kref_put(). Add SLAB_TYPESAFE_BY_RCU as it ensures that the memory freed by kmem_cache_free() will not be reused for another type until the rcu synchronisation period is over, so an address gotten under rcu read lock is safe to inc_ref() without corrupting random memory while the lock is held. Link: http://lkml.kernel.org/r/1535626341-20693-1-git-send-email-asmadeus@codewreck.org Co-developed-by: Dominique Martinet <dominique.martinet@cea.fr> Signed-off-by: Tomas Bortoli <tomasbortoli@gmail.com> Reported-by: syzbot+467050c1ce275af2a5b8@syzkaller.appspotmail.com Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2018-09-079p: embed fcall in req to round down buffer allocsDominique Martinet1-6/+6
'msize' is often a power of two, or at least page-aligned, so avoiding an overhead of two dozen bytes for each allocation will help the allocator do its work and reduce memory fragmentation. Link: http://lkml.kernel.org/r/1533825236-22896-1-git-send-email-asmadeus@codewreck.org Suggested-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr> Reviewed-by: Greg Kurz <groug@kaod.org> Acked-by: Jun Piao <piaojun@huawei.com> Cc: Matthew Wilcox <willy@infradead.org>
2018-08-279p/xen: fix check for xenbus_read error in front_probeDominique Martinet1-2/+2
If the xen bus exists but does not expose the proper interface, it is possible to get a non-zero length but still some error, leading to strcmp failing trying to load invalid memory addresses e.g. fffffffffffffffe. There is then no need to check length when there is no error, as the xenbus driver guarantees that the string is nul-terminated. Link: http://lkml.kernel.org/r/1534236007-10170-1-git-send-email-asmadeus@codewreck.org Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Cc: Eric Van Hensbergen <ericvh@gmail.com> Cc: Latchesar Ionkov <lucho@ionkov.net>
2018-08-139p: fix multiple NULL-pointer-dereferencesTomas Bortoli1-0/+3
Added checks to prevent GPFs from raising. Link: http://lkml.kernel.org/r/20180727110558.5479-1-tomasbortoli@gmail.com Signed-off-by: Tomas Bortoli <tomasbortoli@gmail.com> Reported-by: syzbot+1a262da37d3bead15c39@syzkaller.appspotmail.com Cc: stable@vger.kernel.org Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2018-06-08net/9p/trans_xen.c: don't inclide rwlock.h directlySebastian Andrzej Siewior1-1/+0
rwlock.h should not be included directly. Instead linux/splinlock.h should be included. One thing it does is to break the RT build. Link: http://lkml.kernel.org/r/20180504100319.11880-1-bigeasy@linutronix.de Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Eric Van Hensbergen <ericvh@gmail.com> Cc: Ron Minnich <rminnich@sandia.gov> Cc: Latchesar Ionkov <lucho@ionkov.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-05-10net/9p: fix spelling mistake: "suspsend" -> "suspend"Colin Ian King1-1/+1
Trivial fix to spelling mistake in dev_warn message text Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-159p: add missing module license for xen transportStephen Hemminger1-0/+4
The 9P of Xen module is missing required license and module information. See https://bugzilla.kernel.org/show_bug.cgi?id=198109 Reported-by: Alan Bartlett <ajb@elrepo.org> Fixes: 868eb122739a ("xen/9pfs: introduce Xen 9pfs transport driver") Signed-off-by: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-24net/9p: Switch to wait_event_killable()Tuomas Tynkkynen1-2/+2
Because userspace gets Very Unhappy when calls like stat() and execve() return -EINTR on 9p filesystem mounts. For instance, when bash is looking in PATH for things to execute and some SIGCHLD interrupts stat(), bash can throw a spurious 'command not found' since it doesn't retry the stat(). In practice, hitting the problem is rare and needs a really slow/bogged down 9p server. Cc: stable@vger.kernel.org Signed-off-by: Tuomas Tynkkynen <tuomas@tuxera.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-05-18xen/9pfs: p9_trans_xen_init and p9_trans_xen_exit can be staticWei Yongjun1-2/+2
Fixes the following sparse warnings: net/9p/trans_xen.c:528:5: warning: symbol 'p9_trans_xen_init' was not declared. Should it be static? net/9p/trans_xen.c:540:6: warning: symbol 'p9_trans_xen_exit' was not declared. Should it be static? Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
2017-05-18xen/9pfs: fix return value check in xen_9pfs_front_probe()Wei Yongjun1-2/+2
In case of error, the function xenbus_read() returns ERR_PTR() and never returns NULL. The NULL test in the return value check should be replaced with IS_ERR(). Fixes: 71ebd71921e4 ("xen/9pfs: connect to the backend") Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
2017-05-02xen/9pfs: initialize len to 0 to detect xenbus_read errorsStefano Stabellini1-1/+1
In order to use "len" to check for xenbus_read errors properly, we need to initialize len to 0 before passing it to xenbus_read. CC: dan.carpenter@oracle.com CC: jgross@suse.com CC: boris.ostrovsky@oracle.com CC: Eric Van Hensbergen <ericvh@gmail.com> CC: Ron Minnich <rminnich@sandia.gov> CC: Latchesar Ionkov <lucho@ionkov.net> CC: v9fs-developer@lists.sourceforge.net Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2017-05-02xen/9pfs: receive responsesStefano Stabellini1-0/+56
Upon receiving a notification from the backend, schedule the p9_xen_response work_struct. p9_xen_response checks if any responses are available, if so, it reads them one by one, calling p9_client_cb to send them up to the 9p layer (p9_client_cb completes the request). Handle the ring following the Xen 9pfs specification. CC: groug@kaod.org CC: jgross@suse.com CC: Eric Van Hensbergen <ericvh@gmail.com> CC: Ron Minnich <rminnich@sandia.gov> CC: Latchesar Ionkov <lucho@ionkov.net> CC: v9fs-developer@lists.sourceforge.net Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2017-05-02xen/9pfs: send requests to the backendStefano Stabellini1-2/+85
Implement struct p9_trans_module create and close functions by looking at the available Xen 9pfs frontend-backend connections. We don't expect many frontend-backend connections, thus walking a list is OK. Send requests to the backend by copying each request to one of the available rings (each frontend-backend connection comes with multiple rings). Handle the ring and notifications following the 9pfs specification. If there are not enough free bytes on the ring for the request, wait on the wait_queue: the backend will send a notification after consuming more requests. CC: groug@kaod.org CC: jgross@suse.com CC: Eric Van Hensbergen <ericvh@gmail.com> CC: Ron Minnich <rminnich@sandia.gov> CC: Latchesar Ionkov <lucho@ionkov.net> CC: v9fs-developer@lists.sourceforge.net Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2017-05-02xen/9pfs: connect to the backendStefano Stabellini1-0/+281
Implement functions to handle the xenbus handshake. Upon connection, allocate the rings according to the protocol specification. Initialize a work_struct and a wait_queue. The work_struct will be used to schedule work upon receiving an event channel notification from the backend. The wait_queue will be used to wait when the ring is full and we need to send a new request. CC: groug@kaod.org CC: boris.ostrovsky@oracle.com CC: jgross@suse.com CC: Eric Van Hensbergen <ericvh@gmail.com> CC: Ron Minnich <rminnich@sandia.gov> CC: Latchesar Ionkov <lucho@ionkov.net> CC: v9fs-developer@lists.sourceforge.net Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2017-05-02xen/9pfs: introduce Xen 9pfs transport driverStefano Stabellini1-0/+125
Introduce the Xen 9pfs transport driver: add struct xenbus_driver to register as a xenbus driver and add struct p9_trans_module to register as v9fs driver. All functions are empty stubs for now. CC: groug@kaod.org CC: jgross@suse.com CC: Eric Van Hensbergen <ericvh@gmail.com> CC: Ron Minnich <rminnich@sandia.gov> CC: Latchesar Ionkov <lucho@ionkov.net> CC: v9fs-developer@lists.sourceforge.net Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
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