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skd: Optimize locking

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Only take skdev->lock if necessary.

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Bart Van Assche 2017-08-17 13:13:37 -07:00 committed by Jens Axboe
parent e2bb554827
commit 74c74282c5
1 changed files with 15 additions and 6 deletions
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21
drivers/block/skd_main.c
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@ -490,7 +490,7 @@ static void skd_process_request(struct request *req, bool last)
const u32 tag = blk_mq_unique_tag(req);
struct skd_request_context *const skreq = blk_mq_rq_to_pdu(req);
struct skd_scsi_request *scsi_req;
unsigned long flags;
unsigned long flags = 0;
const u32 lba = blk_rq_pos(req);
const u32 count = blk_rq_sectors(req);
const int data_dir = rq_data_dir(req);
@ -525,9 +525,13 @@ static void skd_process_request(struct request *req, bool last)
sizeof(struct fit_sg_descriptor),
DMA_TO_DEVICE);
spin_lock_irqsave(&skdev->lock, flags);
/* Either a FIT msg is in progress or we have to start one. */
skmsg = skdev->skmsg;
if (skd_max_req_per_msg == 1) {
skmsg = NULL;
} else {
spin_lock_irqsave(&skdev->lock, flags);
skmsg = skdev->skmsg;
}
if (!skmsg) {
skmsg = &skdev->skmsg_table[tag];
skdev->skmsg = skmsg;
@ -574,11 +578,16 @@ static void skd_process_request(struct request *req, bool last)
/*
* If the FIT msg buffer is full send it.
*/
if (last || fmh->num_protocol_cmds_coalesced >= skd_max_req_per_msg) {
if (skd_max_req_per_msg == 1) {
skd_send_fitmsg(skdev, skmsg);
skdev->skmsg = NULL;
} else {
if (last ||
fmh->num_protocol_cmds_coalesced >= skd_max_req_per_msg) {
skd_send_fitmsg(skdev, skmsg);
skdev->skmsg = NULL;
}
spin_unlock_irqrestore(&skdev->lock, flags);
}
spin_unlock_irqrestore(&skdev->lock, flags);
}
static blk_status_t skd_mq_queue_rq(struct blk_mq_hw_ctx *hctx,