mmc: queue: Share mmc request array between partitions

eMMC can have multiple internal partitions that are represented as separate
disks / queues. However switching between partitions is only done when the
queue is empty. Consequently the array of mmc requests that are queued can
be shared between partitions saving memory.

Keep a pointer to the mmc request queue on the card, and use that instead
of allocating a new one for each partition.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

1 files changed, 139 insertions, 95 deletions

diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
index 4a2045527b62..3423b7acf744 100644
--- a/drivers/mmc/core/queue.c
+++ b/drivers/mmc/core/queue.c
@@ -149,17 +149,13 @@ static void mmc_request_fn(struct request_queue *q)
                 wake_up_process(mq->thread);
 }
 
-static struct scatterlist *mmc_alloc_sg(int sg_len, int *err)
+static struct scatterlist *mmc_alloc_sg(int sg_len)
 {
         struct scatterlist *sg;
 
         sg = kmalloc_array(sg_len, sizeof(*sg), GFP_KERNEL);
-        if (!sg)
-                *err = -ENOMEM;
-        else {
-                *err = 0;
+        if (sg)
                 sg_init_table(sg, sg_len);
-        }
 
         return sg;
 }
@@ -185,6 +181,32 @@ static void mmc_queue_setup_discard(struct request_queue *q,
                 queue_flag_set_unlocked(QUEUE_FLAG_SECERASE, q);
 }
 
+static void mmc_queue_req_free_bufs(struct mmc_queue_req *mqrq)
+{
+        kfree(mqrq->bounce_sg);
+        mqrq->bounce_sg = NULL;
+
+        kfree(mqrq->sg);
+        mqrq->sg = NULL;
+
+        kfree(mqrq->bounce_buf);
+        mqrq->bounce_buf = NULL;
+}
+
+static void mmc_queue_reqs_free_bufs(struct mmc_queue_req *mqrq, int qdepth)
+{
+        int i;
+
+        for (i = 0; i < qdepth; i++)
+                mmc_queue_req_free_bufs(&mqrq[i]);
+}
+
+static void mmc_queue_free_mqrqs(struct mmc_queue_req *mqrq, int qdepth)
+{
+        mmc_queue_reqs_free_bufs(mqrq, qdepth);
+        kfree(mqrq);
+}
+
 static struct mmc_queue_req *mmc_queue_alloc_mqrqs(int qdepth)
 {
         struct mmc_queue_req *mqrq;
@@ -200,79 +222,137 @@ static struct mmc_queue_req *mmc_queue_alloc_mqrqs(int qdepth)
 }
 
 #ifdef CONFIG_MMC_BLOCK_BOUNCE
-static bool mmc_queue_alloc_bounce_bufs(struct mmc_queue *mq,
-                                        unsigned int bouncesz)
+static int mmc_queue_alloc_bounce_bufs(struct mmc_queue_req *mqrq, int qdepth,
+                                       unsigned int bouncesz)
 {
         int i;
 
-        for (i = 0; i < mq->qdepth; i++) {
-                mq->mqrq[i].bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
-                if (!mq->mqrq[i].bounce_buf)
-                        goto out_err;
-        }
+        for (i = 0; i < qdepth; i++) {
+                mqrq[i].bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
+                if (!mqrq[i].bounce_buf)
+                        return -ENOMEM;
 
-        return true;
+                mqrq[i].sg = mmc_alloc_sg(1);
+                if (!mqrq[i].sg)
+                        return -ENOMEM;
 
-out_err:
-        while (--i >= 0) {
-                kfree(mq->mqrq[i].bounce_buf);
-                mq->mqrq[i].bounce_buf = NULL;
+                mqrq[i].bounce_sg = mmc_alloc_sg(bouncesz / 512);
+                if (!mqrq[i].bounce_sg)
+                        return -ENOMEM;
         }
-        pr_warn("%s: unable to allocate bounce buffers\n",
-                mmc_card_name(mq->card));
-        return false;
+
+        return 0;
 }
 
-static int mmc_queue_alloc_bounce_sgs(struct mmc_queue *mq,
-                                      unsigned int bouncesz)
+static bool mmc_queue_alloc_bounce(struct mmc_queue_req *mqrq, int qdepth,
+                                   unsigned int bouncesz)
 {
-        int i, ret;
+        int ret;
 
-        for (i = 0; i < mq->qdepth; i++) {
-                mq->mqrq[i].sg = mmc_alloc_sg(1, &ret);
-                if (ret)
-                        return ret;
+        ret = mmc_queue_alloc_bounce_bufs(mqrq, qdepth, bouncesz);
+        if (ret)
+                mmc_queue_reqs_free_bufs(mqrq, qdepth);
 
-                mq->mqrq[i].bounce_sg = mmc_alloc_sg(bouncesz / 512, &ret);
-                if (ret)
-                        return ret;
-        }
+        return !ret;
+}
+
+static unsigned int mmc_queue_calc_bouncesz(struct mmc_host *host)
+{
+        unsigned int bouncesz = MMC_QUEUE_BOUNCESZ;
+
+        if (host->max_segs != 1)
+                return 0;
+
+        if (bouncesz > host->max_req_size)
+                bouncesz = host->max_req_size;
+        if (bouncesz > host->max_seg_size)
+                bouncesz = host->max_seg_size;
+        if (bouncesz > host->max_blk_count * 512)
+                bouncesz = host->max_blk_count * 512;
+
+        if (bouncesz <= 512)
+                return 0;
+
+        return bouncesz;
+}
+#else
+static inline bool mmc_queue_alloc_bounce(struct mmc_queue_req *mqrq,
+                                          int qdepth, unsigned int bouncesz)
+{
+        return false;
+}
 
+static unsigned int mmc_queue_calc_bouncesz(struct mmc_host *host)
+{
         return 0;
 }
 #endif
 
-static int mmc_queue_alloc_sgs(struct mmc_queue *mq, int max_segs)
+static int mmc_queue_alloc_sgs(struct mmc_queue_req *mqrq, int qdepth,
+                               int max_segs)
 {
-        int i, ret;
+        int i;
 
-        for (i = 0; i < mq->qdepth; i++) {
-                mq->mqrq[i].sg = mmc_alloc_sg(max_segs, &ret);
-                if (ret)
-                        return ret;
+        for (i = 0; i < qdepth; i++) {
+                mqrq[i].sg = mmc_alloc_sg(max_segs);
+                if (!mqrq[i].sg)
+                        return -ENOMEM;
         }
 
         return 0;
 }
 
-static void mmc_queue_req_free_bufs(struct mmc_queue_req *mqrq)
+void mmc_queue_free_shared_queue(struct mmc_card *card)
 {
-        kfree(mqrq->bounce_sg);
-        mqrq->bounce_sg = NULL;
+        if (card->mqrq) {
+                mmc_queue_free_mqrqs(card->mqrq, card->qdepth);
+                card->mqrq = NULL;
+        }
+}
 
-        kfree(mqrq->sg);
-        mqrq->sg = NULL;
+static int __mmc_queue_alloc_shared_queue(struct mmc_card *card, int qdepth)
+{
+        struct mmc_host *host = card->host;
+        struct mmc_queue_req *mqrq;
+        unsigned int bouncesz;
+        int ret = 0;
 
-        kfree(mqrq->bounce_buf);
-        mqrq->bounce_buf = NULL;
+        if (card->mqrq)
+                return -EINVAL;
+
+        mqrq = mmc_queue_alloc_mqrqs(qdepth);
+        if (!mqrq)
+                return -ENOMEM;
+
+        card->mqrq = mqrq;
+        card->qdepth = qdepth;
+
+        bouncesz = mmc_queue_calc_bouncesz(host);
+
+        if (bouncesz && !mmc_queue_alloc_bounce(mqrq, qdepth, bouncesz)) {
+                bouncesz = 0;
+                pr_warn("%s: unable to allocate bounce buffers\n",
+                        mmc_card_name(card));
+        }
+
+        card->bouncesz = bouncesz;
+
+        if (!bouncesz) {
+                ret = mmc_queue_alloc_sgs(mqrq, qdepth, host->max_segs);
+                if (ret)
+                        goto out_err;
+        }
+
+        return ret;
+
+out_err:
+        mmc_queue_free_shared_queue(card);
+        return ret;
 }
 
-static void mmc_queue_reqs_free_bufs(struct mmc_queue *mq)
+int mmc_queue_alloc_shared_queue(struct mmc_card *card)
 {
-        int i;
-
-        for (i = 0; i < mq->qdepth; i++)
-                mmc_queue_req_free_bufs(&mq->mqrq[i]);
+        return __mmc_queue_alloc_shared_queue(card, 2);
 }
 
 /**
@@ -289,7 +369,6 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
 {
         struct mmc_host *host = card->host;
         u64 limit = BLK_BOUNCE_HIGH;
-        bool bounce = false;
         int ret = -ENOMEM;
 
         if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
@@ -300,10 +379,8 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
         if (!mq->queue)
                 return -ENOMEM;
 
-        mq->qdepth = 2;
-        mq->mqrq = mmc_queue_alloc_mqrqs(mq->qdepth);
-        if (!mq->mqrq)
-                goto blk_cleanup;
+        mq->mqrq = card->mqrq;
+        mq->qdepth = card->qdepth;
         mq->queue->queuedata = mq;
 
         blk_queue_prep_rq(mq->queue, mmc_prep_request);
@@ -312,44 +389,17 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
         if (mmc_can_erase(card))
                 mmc_queue_setup_discard(mq->queue, card);
 
-#ifdef CONFIG_MMC_BLOCK_BOUNCE
-        if (host->max_segs == 1) {
-                unsigned int bouncesz;
-
-                bouncesz = MMC_QUEUE_BOUNCESZ;
-
-                if (bouncesz > host->max_req_size)
-                        bouncesz = host->max_req_size;
-                if (bouncesz > host->max_seg_size)
-                        bouncesz = host->max_seg_size;
-                if (bouncesz > (host->max_blk_count * 512))
-                        bouncesz = host->max_blk_count * 512;
-
-                if (bouncesz > 512 &&
-                    mmc_queue_alloc_bounce_bufs(mq, bouncesz)) {
-                        blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
-                        blk_queue_max_hw_sectors(mq->queue, bouncesz / 512);
-                        blk_queue_max_segments(mq->queue, bouncesz / 512);
-                        blk_queue_max_segment_size(mq->queue, bouncesz);
-
-                        ret = mmc_queue_alloc_bounce_sgs(mq, bouncesz);
-                        if (ret)
-                                goto cleanup_queue;
-                        bounce = true;
-                }
-        }
-#endif
-
-        if (!bounce) {
+        if (card->bouncesz) {
+                blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
+                blk_queue_max_hw_sectors(mq->queue, card->bouncesz / 512);
+                blk_queue_max_segments(mq->queue, card->bouncesz / 512);
+                blk_queue_max_segment_size(mq->queue, card->bouncesz);
+        } else {
                 blk_queue_bounce_limit(mq->queue, limit);
                 blk_queue_max_hw_sectors(mq->queue,
                         min(host->max_blk_count, host->max_req_size / 512));
                 blk_queue_max_segments(mq->queue, host->max_segs);
                 blk_queue_max_segment_size(mq->queue, host->max_seg_size);
-
-                ret = mmc_queue_alloc_sgs(mq, host->max_segs);
-                if (ret)
-                        goto cleanup_queue;
         }
 
         sema_init(&mq->thread_sem, 1);
@@ -364,11 +414,8 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
 
         return 0;
 
- cleanup_queue:
-        mmc_queue_reqs_free_bufs(mq);
-        kfree(mq->mqrq);
+cleanup_queue:
         mq->mqrq = NULL;
-blk_cleanup:
         blk_cleanup_queue(mq->queue);
         return ret;
 }
@@ -390,10 +437,7 @@ void mmc_cleanup_queue(struct mmc_queue *mq)
         blk_start_queue(q);
         spin_unlock_irqrestore(q->queue_lock, flags);
 
-        mmc_queue_reqs_free_bufs(mq);
-        kfree(mq->mqrq);
         mq->mqrq = NULL;
-
         mq->card = NULL;
 }
 EXPORT_SYMBOL(mmc_cleanup_queue);