BMC/Intel-BMC/linux.git/include/scsi/scsi_host.h, branch dev-5.7

scsi: Replace zero-length array with flexible-array member

2020-03-12T03:07:56+00:00

The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Link: https://lore.kernel.org/r/20200224161406.GA21454@embeddedor Reviewed-by: Lee Duncan Reviewed-by: Satish Kharat Signed-off-by: Gustavo A. R. Silva Signed-off-by: Martin K. Petersen

scsi: core: Introduce {init,exit}_cmd_priv()

2020-02-29T02:02:10+00:00

The current behavior of the SCSI core is to clear driver-private data before preparing a request for submission to the SCSI LLD. Make it possible for SCSI LLDs to disable clearing of driver-private data. These hooks will be used by a later patch, namely "scsi: ufs: Let the SCSI core allocate per-command UFS data". Link: https://lore.kernel.org/r/20200123035637.21848-2-bvanassche@acm.org Cc: Tomas Winkler Cc: Stanley Chu Cc: Bean Huo Cc: Avri Altman Cc: Can Guo Cc: Ming Lei Cc: Johannes Thumshirn Cc: Hannes Reinecke Cc: Christoph Hellwig Signed-off-by: Bart Van Assche Signed-off-by: Martin K. Petersen

scsi: core: Remove cmd_list functionality

2020-02-29T01:54:55+00:00

Remove cmd_list functionality; no users left. With that the scsi_put_command() becomes empty, so remove that one, too. Link: https://lore.kernel.org/r/20200228075318.91255-14-hare@suse.de Reviewed-by: Christoph Hellwig Reviewed-by: Bart van Assche Signed-off-by: Hannes Reinecke Signed-off-by: Martin K. Petersen

scsi: core: add scsi_host_busy_iter()

2020-02-29T01:54:52+00:00

Add an iterator scsi_host_busy_iter() to traverse all busy commands. If locking against concurrent command completions is required, it has to be provided by the caller. Link: https://lore.kernel.org/r/20200228075318.91255-11-hare@suse.de Signed-off-by: Hannes Reinecke Signed-off-by: Martin K. Petersen

scsi: core: add scsi_host_(block,unblock) helper function

2020-02-29T01:54:51+00:00

Add helper functions to call scsi_internal_device_block()/ scsi_internal_device_unblock() for all attached devices on a SCSI host. Link: https://lore.kernel.org/r/20200228075318.91255-9-hare@suse.de Reviewed-by: Christoph Hellwig Reviewed-by: Bart Van Assche Signed-off-by: Hannes Reinecke Signed-off-by: Martin K. Petersen

scsi: core: add scsi_host_complete_all_commands() helper

2020-02-29T01:54:47+00:00

Add a helper scsi_host_complete_all_commands() to terminate all outstanding commands on a SCSI host. Link: https://lore.kernel.org/r/20200228075318.91255-3-hare@suse.de Signed-off-by: Hannes Reinecke Signed-off-by: Martin K. Petersen

scsi: core: remove .for_blk_mq

2020-02-11T03:46:55+00:00

Not in use anymore. Remove the flag. Cc: Sathya Prakash Cc: Chaitra P B Cc: Suganath Prabu Subramani Cc: Kashyap Desai Cc: Sumit Saxena Cc: Shivasharan S Cc: Ewan D. Milne Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Bart Van Assche Link: https://lore.kernel.org/r/20200119071432.18558-3-ming.lei@redhat.com Reviewed-by: Christoph Hellwig Signed-off-by: Ming Lei Signed-off-by: Martin K. Petersen

scsi: core: Clean up SG_NONE

2019-11-13T03:21:35+00:00

Remove SG_NONE and a related misleading comment. Update documentation. This patch does not affect behaviour as zero initialization is redundant. Cc: Jonathan Corbet Cc: Bartlomiej Zolnierkiewicz Cc: Jens Axboe Cc: Viresh Kumar Cc: Oliver Neukum Cc: Alan Stern Cc: Greg Kroah-Hartman Cc: usb-storage@lists.one-eyed-alien.net Link: https://lore.kernel.org/r/b4779b7a6563f6bd8d259ee457871c1c463c420e.1572656814.git.fthain@telegraphics.com.au Signed-off-by: Finn Thain Signed-off-by: Martin K. Petersen

scsi: core: avoid host-wide host_busy counter for scsi_mq

2019-11-02T00:12:50+00:00

It isn't necessary to check the host depth in scsi_queue_rq() any more since it has been respected by blk-mq before calling scsi_queue_rq() via getting driver tag. Lots of LUNs may attach to same host and per-host IOPS may reach millions, so we should avoid expensive atomic operations on the host-wide counter in the IO path. This patch implements scsi_host_busy() via blk_mq_tagset_busy_iter() with one scsi command state for reading the count of busy IOs for scsi_mq. It is observed that IOPS is increased by 15% in IO test on scsi_debug (32 LUNs, 32 submit queues, 1024 can_queue, libaio/dio) in a dual-socket system. Cc: Jens Axboe Cc: Ewan D. Milne Cc: Omar Sandoval , Cc: "Martin K. Petersen" , Cc: James Bottomley , Cc: Christoph Hellwig , Cc: Kashyap Desai Cc: Hannes Reinecke Cc: Laurence Oberman Cc: Bart Van Assche Link: https://lore.kernel.org/r/20191025065855.6309-1-ming.lei@redhat.com Signed-off-by: Ming Lei Reviewed-by: Jens Axboe Reviewed-by: Bart Van Assche Signed-off-by: Martin K. Petersen

scsi: core: allow auto suspend override by low-level driver

2019-10-01T03:01:17+00:00

Rework from previous work by: Sujit Reddy Thumma Until now the scsi mid-layer forbids runtime suspend till userspace enables it. This is mainly to quarantine some disks with broken runtime power management or have high latencies executing suspend resume callbacks. If the userspace doesn't enable the runtime suspend the underlying hardware will be always on even when it is not doing any useful work and thus wasting power. Some low-level drivers for the controllers can efficiently use runtime power management to reduce power consumption and improve battery life. Allow runtime suspend parameters override within the LLD itself instead of waiting for userspace to control the power management. Link: https://lore.kernel.org/r/1568649411-5127-2-git-send-email-stanley.chu@mediatek.com Reviewed-by: Avri Altman Reviewed-by: Bart Van Assche Signed-off-by: Stanley Chu Signed-off-by: Martin K. Petersen