From 79ed24297236b7430d6ce0a1511ff70cf5b6015a Mon Sep 17 00:00:00 2001 From: James Bottomley Date: Tue, 6 Jan 2009 13:15:20 -0600 Subject: [PATCH] [SCSI] scsi_lib: fix DID_RESET status problems Andrew Vaszquez said: > There's a problem that is causing commands returned by the LLD with > a DID_RESET status to be reissued with cleared cmd->sdb data which > in our tests are manifesting in firmware detected overruns. Here's > a snippet of a READ_10 scsi_cmnd upon completion by the storage The problem is caused by: commit b60af5b0adf0da24c673598c8d3fb4d4189a15ce Author: Alan Stern Date: Mon Nov 3 15:56:47 2008 -0500 [SCSI] simplify scsi_io_completion() Because scsi_release_buffers() is called before commands that go through the ACTION_RETRY and ACTION_DELAYED_RETRY legs are requeued. However, they're not re-prepared, so nothing ever reallocates the buffer resources to them. Fix this by releasing the buffers only if we're not going to go down these legs (but scsi_release_buffers() on all legs including two in scsi_end_request(); this latter needs a special version __scsi_release_buffers() because the final one can be called after the request has been freed, so the bidi test in scsi_release_buffers(), which touches the request has to be skipped). Reported-by: Andrew Vasquez Signed-off-by: James Bottomley --- drivers/scsi/scsi_lib.c | 43 ++++++++++++++++++++++++++--------------- 1 file changed, 27 insertions(+), 16 deletions(-) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index cc613bae4ad..940dc32ff0d 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -701,6 +701,8 @@ void scsi_run_host_queues(struct Scsi_Host *shost) scsi_run_queue(sdev->request_queue); } +static void __scsi_release_buffers(struct scsi_cmnd *, int); + /* * Function: scsi_end_request() * @@ -749,6 +751,7 @@ static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error, * leftovers in the front of the * queue, and goose the queue again. */ + scsi_release_buffers(cmd); scsi_requeue_command(q, cmd); cmd = NULL; } @@ -760,6 +763,7 @@ static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error, * This will goose the queue request function at the end, so we don't * need to worry about launching another command. */ + __scsi_release_buffers(cmd, 0); scsi_next_command(cmd); return NULL; } @@ -815,6 +819,26 @@ static void scsi_free_sgtable(struct scsi_data_buffer *sdb) __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free); } +static void __scsi_release_buffers(struct scsi_cmnd *cmd, int do_bidi_check) +{ + + if (cmd->sdb.table.nents) + scsi_free_sgtable(&cmd->sdb); + + memset(&cmd->sdb, 0, sizeof(cmd->sdb)); + + if (do_bidi_check && scsi_bidi_cmnd(cmd)) { + struct scsi_data_buffer *bidi_sdb = + cmd->request->next_rq->special; + scsi_free_sgtable(bidi_sdb); + kmem_cache_free(scsi_sdb_cache, bidi_sdb); + cmd->request->next_rq->special = NULL; + } + + if (scsi_prot_sg_count(cmd)) + scsi_free_sgtable(cmd->prot_sdb); +} + /* * Function: scsi_release_buffers() * @@ -834,21 +858,7 @@ static void scsi_free_sgtable(struct scsi_data_buffer *sdb) */ void scsi_release_buffers(struct scsi_cmnd *cmd) { - if (cmd->sdb.table.nents) - scsi_free_sgtable(&cmd->sdb); - - memset(&cmd->sdb, 0, sizeof(cmd->sdb)); - - if (scsi_bidi_cmnd(cmd)) { - struct scsi_data_buffer *bidi_sdb = - cmd->request->next_rq->special; - scsi_free_sgtable(bidi_sdb); - kmem_cache_free(scsi_sdb_cache, bidi_sdb); - cmd->request->next_rq->special = NULL; - } - - if (scsi_prot_sg_count(cmd)) - scsi_free_sgtable(cmd->prot_sdb); + __scsi_release_buffers(cmd, 1); } EXPORT_SYMBOL(scsi_release_buffers); @@ -962,7 +972,6 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) } BUG_ON(blk_bidi_rq(req)); /* bidi not support for !blk_pc_request yet */ - scsi_release_buffers(cmd); /* * Next deal with any sectors which we were able to correctly @@ -1080,6 +1089,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) switch (action) { case ACTION_FAIL: /* Give up and fail the remainder of the request */ + scsi_release_buffers(cmd); if (!(req->cmd_flags & REQ_QUIET)) { if (description) scmd_printk(KERN_INFO, cmd, "%s\n", @@ -1095,6 +1105,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) /* Unprep the request and put it back at the head of the queue. * A new command will be prepared and issued. */ + scsi_release_buffers(cmd); scsi_requeue_command(q, cmd); break; case ACTION_RETRY: -- 2.41.1