block: simplify and cleanup bvec pool handling

Instead of a flag and an index just make sure an index of 0 means
no need to free the bvec array.  Also move the constants related
to the bvec pools together and use a consistent naming scheme for
them.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index 711e4d8de6fa06020432da0f37a9edcdd67a6151..11633fca27d304cf8b60d2e6e74022a7b8fa3500 100644 (file)
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -53,7 +53,6 @@ struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
 {
        struct bio_integrity_payload *bip;
        struct bio_set *bs = bio->bi_pool;
-       unsigned long idx = BIO_POOL_NONE;
        unsigned inline_vecs;
 
        if (!bs || !bs->bio_integrity_pool) {
@@ -71,17 +70,19 @@ struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
        memset(bip, 0, sizeof(*bip));
 
        if (nr_vecs > inline_vecs) {
+               unsigned long idx = 0;
+
                bip->bip_vec = bvec_alloc(gfp_mask, nr_vecs, &idx,
                                          bs->bvec_integrity_pool);
                if (!bip->bip_vec)
                        goto err;
                bip->bip_max_vcnt = bvec_nr_vecs(idx);
+               bip->bip_slab = idx;
        } else {
                bip->bip_vec = bip->bip_inline_vecs;
                bip->bip_max_vcnt = inline_vecs;
        }
 
-       bip->bip_slab = idx;
        bip->bip_bio = bio;
        bio->bi_integrity = bip;
        bio->bi_rw |= REQ_INTEGRITY;
@@ -110,9 +111,7 @@ void bio_integrity_free(struct bio *bio)
                      bip->bip_vec->bv_offset);
 
        if (bs && bs->bio_integrity_pool) {
-               if (bip->bip_slab != BIO_POOL_NONE)
-                       bvec_free(bs->bvec_integrity_pool, bip->bip_vec,
-                                 bip->bip_slab);
+               bvec_free(bs->bvec_integrity_pool, bip->bip_vec, bip->bip_slab);
 
                mempool_free(bip, bs->bio_integrity_pool);
        } else {

diff --git a/block/bio.c b/block/bio.c
index 848cd351513bad7fb44b176c0205a614fa314a52..882b50ae3ad6259057970b50d2793132d83d229b 100644 (file)
--- a/block/bio.c
+++ b/block/bio.c
@@ -43,7 +43,7 @@
  * unsigned short
  */
 #define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
-static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
+static struct biovec_slab bvec_slabs[BVEC_POOL_NR] __read_mostly = {
        BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES),
 };
 #undef BV
@@ -160,11 +160,15 @@ unsigned int bvec_nr_vecs(unsigned short idx)
 
 void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned int idx)
 {
-       BIO_BUG_ON(idx >= BIOVEC_NR_POOLS);
+       if (!idx)
+               return;
+       idx--;
+
+       BIO_BUG_ON(idx >= BVEC_POOL_NR);
 
-       if (idx == BIOVEC_MAX_IDX)
+       if (idx == BVEC_POOL_MAX) {
                mempool_free(bv, pool);
-       else {
+       } else {
                struct biovec_slab *bvs = bvec_slabs + idx;
 
                kmem_cache_free(bvs->slab, bv);
@@ -206,7 +210,7 @@ struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx,
         * idx now points to the pool we want to allocate from. only the
         * 1-vec entry pool is mempool backed.
         */
-       if (*idx == BIOVEC_MAX_IDX) {
+       if (*idx == BVEC_POOL_MAX) {
 fallback:
                bvl = mempool_alloc(pool, gfp_mask);
        } else {
@@ -226,11 +230,12 @@ fallback:
                 */
                bvl = kmem_cache_alloc(bvs->slab, __gfp_mask);
                if (unlikely(!bvl && (gfp_mask & __GFP_DIRECT_RECLAIM))) {
-                       *idx = BIOVEC_MAX_IDX;
+                       *idx = BVEC_POOL_MAX;
                        goto fallback;
                }
        }
 
+       (*idx)++;
        return bvl;
 }
 
@@ -250,8 +255,7 @@ static void bio_free(struct bio *bio)
        __bio_free(bio);
 
        if (bs) {
-               if (bio_flagged(bio, BIO_OWNS_VEC))
-                       bvec_free(bs->bvec_pool, bio->bi_io_vec, BIO_POOL_IDX(bio));
+               bvec_free(bs->bvec_pool, bio->bi_io_vec, BVEC_POOL_IDX(bio));
 
                /*
                 * If we have front padding, adjust the bio pointer before freeing
@@ -420,7 +424,6 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
        gfp_t saved_gfp = gfp_mask;
        unsigned front_pad;
        unsigned inline_vecs;
-       unsigned long idx = BIO_POOL_NONE;
        struct bio_vec *bvl = NULL;
        struct bio *bio;
        void *p;
@@ -480,6 +483,8 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
        bio_init(bio);
 
        if (nr_iovecs > inline_vecs) {
+               unsigned long idx = 0;
+
                bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
                if (!bvl && gfp_mask != saved_gfp) {
                        punt_bios_to_rescuer(bs);
@@ -490,13 +495,12 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
                if (unlikely(!bvl))
                        goto err_free;
 
-               bio_set_flag(bio, BIO_OWNS_VEC);
+               bio->bi_flags |= idx << BVEC_POOL_OFFSET;
        } else if (nr_iovecs) {
                bvl = bio->bi_inline_vecs;
        }
 
        bio->bi_pool = bs;
-       bio->bi_flags |= idx << BIO_POOL_OFFSET;
        bio->bi_max_vecs = nr_iovecs;
        bio->bi_io_vec = bvl;
        return bio;
@@ -568,7 +572,7 @@ EXPORT_SYMBOL(bio_phys_segments);
  */
 void __bio_clone_fast(struct bio *bio, struct bio *bio_src)
 {
-       BUG_ON(bio->bi_pool && BIO_POOL_IDX(bio) != BIO_POOL_NONE);
+       BUG_ON(bio->bi_pool && BVEC_POOL_IDX(bio));
 
        /*
         * most users will be overriding ->bi_bdev with a new target,
@@ -1832,7 +1836,7 @@ EXPORT_SYMBOL_GPL(bio_trim);
  */
 mempool_t *biovec_create_pool(int pool_entries)
 {
-       struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX;
+       struct biovec_slab *bp = bvec_slabs + BVEC_POOL_MAX;
 
        return mempool_create_slab_pool(pool_entries, bp->slab);
 }
@@ -2009,7 +2013,7 @@ static void __init biovec_init_slabs(void)
 {
        int i;
 
-       for (i = 0; i < BIOVEC_NR_POOLS; i++) {
+       for (i = 0; i < BVEC_POOL_NR; i++) {
                int size;
                struct biovec_slab *bvs = bvec_slabs + i;
 

diff --git a/drivers/md/bcache/io.c b/drivers/md/bcache/io.c
index fd885cc2afad4a5caae3042f73c6d862db2e3bf1..e97b0acf7b8dca4a04e2018d23d2c79c051e248b 100644 (file)
--- a/drivers/md/bcache/io.c
+++ b/drivers/md/bcache/io.c
@@ -25,7 +25,6 @@ struct bio *bch_bbio_alloc(struct cache_set *c)
        struct bio *bio = &b->bio;
 
        bio_init(bio);
-       bio->bi_flags           |= BIO_POOL_NONE << BIO_POOL_OFFSET;
        bio->bi_max_vecs         = bucket_pages(c);
        bio->bi_io_vec           = bio->bi_inline_vecs;
 

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 0bbb2e332410f6a83e16f4fead7d3db84e3a34ba..141cfa95a185519f61c57b331c068d6e1958e091 100644 (file)
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -715,8 +715,6 @@ static inline void bio_inc_remaining(struct bio *bio)
  * and the bvec_slabs[].
  */
 #define BIO_POOL_SIZE 2
-#define BIOVEC_NR_POOLS 6
-#define BIOVEC_MAX_IDX (BIOVEC_NR_POOLS - 1)
 
 struct bio_set {
        struct kmem_cache *bio_slab;

diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index efba1f2ace2e0d456c588c80978711130a4e551b..b76463ea35877f9d91da76645014fdf1bb2ad437 100644 (file)
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -134,19 +134,25 @@ struct bio {
 
 /*
  * Flags starting here get preserved by bio_reset() - this includes
- * BIO_POOL_IDX()
+ * BVEC_POOL_IDX()
  */
 #define BIO_RESET_BITS 13
-#define BIO_OWNS_VEC   13      /* bio_free() should free bvec */
 
 /*
- * top 4 bits of bio flags indicate the pool this bio came from
+ * We support 6 different bvec pools, the last one is magic in that it
+ * is backed by a mempool.
  */
-#define BIO_POOL_BITS          (4)
-#define BIO_POOL_NONE          ((1UL << BIO_POOL_BITS) - 1)
-#define BIO_POOL_OFFSET                (32 - BIO_POOL_BITS)
-#define BIO_POOL_MASK          (1UL << BIO_POOL_OFFSET)
-#define BIO_POOL_IDX(bio)      ((bio)->bi_flags >> BIO_POOL_OFFSET)
+#define BVEC_POOL_NR           6
+#define BVEC_POOL_MAX          (BVEC_POOL_NR - 1)
+
+/*
+ * Top 4 bits of bio flags indicate the pool the bvecs came from.  We add
+ * 1 to the actual index so that 0 indicates that there are no bvecs to be
+ * freed.
+ */
+#define BVEC_POOL_BITS         (4)
+#define BVEC_POOL_OFFSET       (32 - BVEC_POOL_BITS)
+#define BVEC_POOL_IDX(bio)     ((bio)->bi_flags >> BVEC_POOL_OFFSET)
 
 #endif /* CONFIG_BLOCK */