Revision bba0bdd7ad4713d82338bcd9b72d57e9335a664b authored by Bart Van Assche on 04 March 2015, 09:31:47 UTC, committed by James Bottomley on 08 April 2015, 16:41:41 UTC
SCSI transport drivers and SCSI LLDs block a SCSI device if the transport layer is not operational. This means that in this state no requests should be processed, even if the REQ_PREEMPT flag has been set. This patch avoids that a rescan shortly after a cable pull sporadically triggers the following kernel oops: BUG: unable to handle kernel paging request at ffffc9001a6bc084 IP: [<ffffffffa04e08f2>] mlx4_ib_post_send+0xd2/0xb30 [mlx4_ib] Process rescan-scsi-bus (pid: 9241, threadinfo ffff88053484a000, task ffff880534aae100) Call Trace: [<ffffffffa0718135>] srp_post_send+0x65/0x70 [ib_srp] [<ffffffffa071b9df>] srp_queuecommand+0x1cf/0x3e0 [ib_srp] [<ffffffffa0001ff1>] scsi_dispatch_cmd+0x101/0x280 [scsi_mod] [<ffffffffa0009ad1>] scsi_request_fn+0x411/0x4d0 [scsi_mod] [<ffffffff81223b37>] __blk_run_queue+0x27/0x30 [<ffffffff8122a8d2>] blk_execute_rq_nowait+0x82/0x110 [<ffffffff8122a9c2>] blk_execute_rq+0x62/0xf0 [<ffffffffa000b0e8>] scsi_execute+0xe8/0x190 [scsi_mod] [<ffffffffa000b2f3>] scsi_execute_req+0xa3/0x130 [scsi_mod] [<ffffffffa000c1aa>] scsi_probe_lun+0x17a/0x450 [scsi_mod] [<ffffffffa000ce86>] scsi_probe_and_add_lun+0x156/0x480 [scsi_mod] [<ffffffffa000dc2f>] __scsi_scan_target+0xdf/0x1f0 [scsi_mod] [<ffffffffa000dfa3>] scsi_scan_host_selected+0x183/0x1c0 [scsi_mod] [<ffffffffa000edfb>] scsi_scan+0xdb/0xe0 [scsi_mod] [<ffffffffa000ee13>] store_scan+0x13/0x20 [scsi_mod] [<ffffffff811c8d9b>] sysfs_write_file+0xcb/0x160 [<ffffffff811589de>] vfs_write+0xce/0x140 [<ffffffff81158b53>] sys_write+0x53/0xa0 [<ffffffff81464592>] system_call_fastpath+0x16/0x1b [<00007f611c9d9300>] 0x7f611c9d92ff Reported-by: Max Gurtuvoy <maxg@mellanox.com> Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Mike Christie <michaelc@cs.wisc.edu> Cc: <stable@vger.kernel.org> Signed-off-by: James Bottomley <JBottomley@Odin.com>
1 parent 2e7cee0
bsearch.c
/*
* A generic implementation of binary search for the Linux kernel
*
* Copyright (C) 2008-2009 Ksplice, Inc.
* Author: Tim Abbott <tabbott@ksplice.com>
*
* 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; version 2.
*/
#include <linux/export.h>
#include <linux/bsearch.h>
/*
* bsearch - binary search an array of elements
* @key: pointer to item being searched for
* @base: pointer to first element to search
* @num: number of elements
* @size: size of each element
* @cmp: pointer to comparison function
*
* This function does a binary search on the given array. The
* contents of the array should already be in ascending sorted order
* under the provided comparison function.
*
* Note that the key need not have the same type as the elements in
* the array, e.g. key could be a string and the comparison function
* could compare the string with the struct's name field. However, if
* the key and elements in the array are of the same type, you can use
* the same comparison function for both sort() and bsearch().
*/
void *bsearch(const void *key, const void *base, size_t num, size_t size,
int (*cmp)(const void *key, const void *elt))
{
size_t start = 0, end = num;
int result;
while (start < end) {
size_t mid = start + (end - start) / 2;
result = cmp(key, base + mid * size);
if (result < 0)
end = mid;
else if (result > 0)
start = mid + 1;
else
return (void *)base + mid * size;
}
return NULL;
}
EXPORT_SYMBOL(bsearch);
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