Re: [PATCH 15/18] scsi: allocate scsi_cmnd structures as part of struct request
From: Bart Van Assche <hidden>
Date: 2017-01-27 18:39:46
Also in:
dm-devel, linux-block, linux-scsi
On Wed, 2017-01-25 at 18:25 +0100, Christoph Hellwig wrote:
quoted hunk ↗ jump to hunk
-unsigned char *scsi_alloc_sense_buffer(struct Scsi_Host *shost, gfp_t gfp_mask, - int numa_node) +static unsigned char *scsi_alloc_sense_buffer(struct Scsi_Host *shost, + gfp_t gfp_mask, int numa_node) { return kmem_cache_alloc_node(scsi_select_sense_cache(shost), gfp_mask, numa_node);@@ -697,14 +696,13 @@ static bool scsi_end_request(struct request *req, int error,if (bidi_bytes) scsi_release_bidi_buffers(cmd); + scsi_release_buffers(cmd); + scsi_put_command(cmd); spin_lock_irqsave(q->queue_lock, flags); blk_finish_request(req, error); spin_unlock_irqrestore(q->queue_lock, flags); - scsi_release_buffers(cmd); - - scsi_put_command(cmd); scsi_run_queue(q); }
Hello Christoph, Why have the scsi_release_buffers() and scsi_put_command(cmd) calls been moved up? I haven't found an explanation for this change in the patch description. Please also consider to remove the cmd->request->special = NULL assignments via this patch. Since this patch makes the lifetime of struct scsi_cmnd and struct request identical these assignments are no longer needed. This patch introduces the function scsi_exit_rq(). Having two functions for the single-queue path that release resources (scsi_release_buffers() and scsi_exit_rq()) is confusing. Since every scsi_release_buffers() call is followed by a blk_unprep_request() call, have you considered to move the scsi_release_buffers() call into scsi_unprep_fn() via an additional patch? Thanks, Bart.