Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756625Ab3DWROU (ORCPT ); Tue, 23 Apr 2013 13:14:20 -0400 Received: from masquerade.micron.com ([137.201.242.130]:25789 "EHLO masquerade.micron.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756487Ab3DWROT (ORCPT ); Tue, 23 Apr 2013 13:14:19 -0400 Message-ID: <5176C163.3090404@micron.com> Date: Tue, 23 Apr 2013 22:44:11 +0530 From: Asai Thambi S P User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: Jens Axboe CC: "linux-kernel@vger.kernel.org" , "Sam Bradshaw" Subject: [PATCH] mtip32xx: Workaround for unaligned writes Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-TM-AS-Product-Ver: SMEX-10.0.0.4152-7.000.1014-19820.000 X-TM-AS-Result: No-9.812100-0.000000-31 X-TM-AS-User-Approved-Sender: Yes X-TM-AS-User-Blocked-Sender: No X-MT-CheckInternalSenderRule: True Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7058 Lines: 224 Workaround for handling unaligned writes: limit number of outstanding unaligned writes Signed-off-by: Sam Bradshaw Signed-off-by: Asai Thambi S P --- drivers/block/mtip32xx/mtip32xx.c | 59 +++++++++++++++++++++++++++++------- drivers/block/mtip32xx/mtip32xx.h | 11 +++++++ 2 files changed, 58 insertions(+), 12 deletions(-) diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c index 30a03ab..c0d3873 100644 --- a/drivers/block/mtip32xx/mtip32xx.c +++ b/drivers/block/mtip32xx/mtip32xx.c @@ -712,7 +712,10 @@ static void mtip_async_complete(struct mtip_port *port, atomic_set(&port->commands[tag].active, 0); release_slot(port, tag); - up(&port->cmd_slot); + if (unlikely(command->unaligned)) + up(&port->cmd_slot_unal); + else + up(&port->cmd_slot); } /* @@ -2557,7 +2560,7 @@ static int mtip_hw_ioctl(struct driver_data *dd, unsigned int cmd, */ static void mtip_hw_submit_io(struct driver_data *dd, sector_t sector, int nsect, int nents, int tag, void *callback, - void *data, int dir) + void *data, int dir, int unaligned) { struct host_to_dev_fis *fis; struct mtip_port *port = dd->port; @@ -2570,6 +2573,7 @@ static void mtip_hw_submit_io(struct driver_data *dd, sector_t sector, command->scatter_ents = nents; + command->unaligned = unaligned; /* * The number of retries for this command before it is * reported as a failure to the upper layers. @@ -2598,6 +2602,9 @@ static void mtip_hw_submit_io(struct driver_data *dd, sector_t sector, fis->res3 = 0; fill_command_sg(dd, command, nents); + if (unaligned) + fis->device |= 1 << 7; + /* Populate the command header */ command->command_header->opts = __force_bit2int cpu_to_le32( @@ -2644,9 +2651,13 @@ static void mtip_hw_submit_io(struct driver_data *dd, sector_t sector, * return value * None */ -static void mtip_hw_release_scatterlist(struct driver_data *dd, int tag) +static void mtip_hw_release_scatterlist(struct driver_data *dd, int tag, + int unaligned) { + struct semaphore *sem = unaligned ? &dd->port->cmd_slot_unal : + &dd->port->cmd_slot; release_slot(dd->port, tag); + up(sem); } /* @@ -2661,22 +2672,25 @@ static void mtip_hw_release_scatterlist(struct driver_data *dd, int tag) * or NULL if no command slots are available. */ static struct scatterlist *mtip_hw_get_scatterlist(struct driver_data *dd, - int *tag) + int *tag, int unaligned) { + struct semaphore *sem = unaligned ? &dd->port->cmd_slot_unal : + &dd->port->cmd_slot; + /* * It is possible that, even with this semaphore, a thread * may think that no command slots are available. Therefore, we * need to make an attempt to get_slot(). */ - down(&dd->port->cmd_slot); + down(sem); *tag = get_slot(dd->port); if (unlikely(test_bit(MTIP_DDF_REMOVE_PENDING_BIT, &dd->dd_flag))) { - up(&dd->port->cmd_slot); + up(sem); return NULL; } if (unlikely(*tag < 0)) { - up(&dd->port->cmd_slot); + up(sem); return NULL; } @@ -2909,6 +2923,11 @@ static inline void hba_setup(struct driver_data *dd) dd->mmio + HOST_HSORG); } +static int mtip_device_unaligned_constrained(struct driver_data *dd) +{ + return (dd->pdev->device == P420M_DEVICE_ID ? 1 : 0); +} + /* * Detect the details of the product, and store anything needed * into the driver data structure. This includes product type and @@ -3131,8 +3150,15 @@ static int mtip_hw_init(struct driver_data *dd) for (i = 0; i < MTIP_MAX_SLOT_GROUPS; i++) dd->work[i].port = dd->port; + /* Enable unaligned IO constraints for some devices */ + if (mtip_device_unaligned_constrained(dd)) + dd->unal_qdepth = MTIP_MAX_UNALIGNED_SLOTS; + else + dd->unal_qdepth = 0; + /* Counting semaphore to track command slot usage */ - sema_init(&dd->port->cmd_slot, num_command_slots - 1); + sema_init(&dd->port->cmd_slot, num_command_slots - 1 - dd->unal_qdepth); + sema_init(&dd->port->cmd_slot_unal, dd->unal_qdepth); /* Spinlock to prevent concurrent issue */ for (i = 0; i < MTIP_MAX_SLOT_GROUPS; i++) @@ -3735,7 +3761,7 @@ static void mtip_make_request(struct request_queue *queue, struct bio *bio) struct scatterlist *sg; struct bio_vec *bvec; int nents = 0; - int tag = 0; + int tag = 0, unaligned = 0; if (unlikely(dd->dd_flag & MTIP_DDF_STOP_IO)) { if (unlikely(test_bit(MTIP_DDF_REMOVE_PENDING_BIT, @@ -3771,7 +3797,15 @@ static void mtip_make_request(struct request_queue *queue, struct bio *bio) return; } - sg = mtip_hw_get_scatterlist(dd, &tag); + if (bio_data_dir(bio) == WRITE && bio_sectors(bio) <= 64 && + dd->unal_qdepth) { + if (bio->bi_sector % 8 != 0) /* Unaligned on 4k boundaries */ + unaligned = 1; + else if (bio_sectors(bio) % 8 != 0) /* Aligned but not 4k/8k */ + unaligned = 1; + } + + sg = mtip_hw_get_scatterlist(dd, &tag, unaligned); if (likely(sg != NULL)) { blk_queue_bounce(queue, &bio); @@ -3779,7 +3813,7 @@ static void mtip_make_request(struct request_queue *queue, struct bio *bio) dev_warn(&dd->pdev->dev, "Maximum number of SGL entries exceeded\n"); bio_io_error(bio); - mtip_hw_release_scatterlist(dd, tag); + mtip_hw_release_scatterlist(dd, tag, unaligned); return; } @@ -3799,7 +3833,8 @@ static void mtip_make_request(struct request_queue *queue, struct bio *bio) tag, bio_endio, bio, - bio_data_dir(bio)); + bio_data_dir(bio), + unaligned); } else bio_io_error(bio); } diff --git a/drivers/block/mtip32xx/mtip32xx.h b/drivers/block/mtip32xx/mtip32xx.h index 3bffff5..579fb84 100644 --- a/drivers/block/mtip32xx/mtip32xx.h +++ b/drivers/block/mtip32xx/mtip32xx.h @@ -52,6 +52,9 @@ #define MTIP_FTL_REBUILD_MAGIC 0xED51 #define MTIP_FTL_REBUILD_TIMEOUT_MS 2400000 +/* unaligned IO handling */ +#define MTIP_MAX_UNALIGNED_SLOTS 8 + /* Macro to extract the tag bit number from a tag value. */ #define MTIP_TAG_BIT(tag) (tag & 0x1F) @@ -333,6 +336,8 @@ struct mtip_cmd { int scatter_ents; /* Number of scatter list entries used */ + int unaligned; /* command is unaligned on 4k boundary */ + struct scatterlist sg[MTIP_MAX_SG]; /* Scatter list entries */ int retries; /* The number of retries left for this command. */ @@ -452,6 +457,10 @@ struct mtip_port { * command slots available. */ struct semaphore cmd_slot; + + /* Semaphore to control queue depth of unaligned IOs */ + struct semaphore cmd_slot_unal; + /* Spinlock for working around command-issue bug. */ spinlock_t cmd_issue_lock[MTIP_MAX_SLOT_GROUPS]; }; @@ -501,6 +510,8 @@ struct driver_data { atomic_t irq_workers_active; int isr_binding; + + int unal_qdepth; /* qdepth of unaligned IO queue */ }; #endif -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/