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Commit5923d64b7a("scsi: libiscsi: Drop taskqueuelock") added an extra task->state because for commit6f8830f5bb("scsi: libiscsi: add lock around task lists to fix list corruption regression") we didn't know why we ended up with cmds on the list and thought it might have been a bad target sending a response while we were still sending the cmd. We were never able to get a target to send us a response early, because it turns out the bug was just a race in libiscsi/libiscsi_tcp where: 1. iscsi_tcp_r2t_rsp() queues a r2t to tcp_task->r2tqueue. 2. iscsi_tcp_task_xmit() runs iscsi_tcp_get_curr_r2t() and sees we have a r2t. It dequeues it and iscsi_tcp_task_xmit() starts to process it. 3. iscsi_tcp_r2t_rsp() runs iscsi_requeue_task() and puts the task on the requeue list. 4. iscsi_tcp_task_xmit() sends the data for r2t. This is the final chunk of data, so the cmd is done. 5. target sends the response. 6. On a different CPU from #3, iscsi_complete_task() processes the response. Since there was no common lock for the list, the lists/tasks pointers are not fully in sync, so could end up with list corruption. Since it was just a race on our side, remove the extra check and fix up the comments. Link: https://lore.kernel.org/r/20220616224557.115234-7-michael.christie@oracle.com Reviewed-by: Wu Bo <wubo40@huawei.com> Reviewed-by: Lee Duncan <lduncan@suse.com> Signed-off-by: Mike Christie <michael.christie@oracle.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.