dm vdo vio-pool: allow variable-sized metadata vios

With larger-sized metadata vio pools, vdo will sometimes need to
issue I/O with a smaller size than the allocated size. Since
vio_reset_bio is where the bvec array and I/O size are initialized,
this reset interface must now specify what I/O size to use.

Signed-off-by: Ken Raeburn <raeburn@redhat.com>
Signed-off-by: Matthew Sakai <msakai@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

diff --git a/drivers/md/dm-vdo/io-submitter.c b/drivers/md/dm-vdo/io-submitter.c
index 421e5436c32c9427c5170f81245128793056a5ee..11d47770b54d2159f5e54bd46cda934629f8fc45 100644 (file)
--- a/drivers/md/dm-vdo/io-submitter.c
+++ b/drivers/md/dm-vdo/io-submitter.c
@@ -327,6 +327,7 @@ void vdo_submit_data_vio(struct data_vio *data_vio)
  * @error_handler: the handler for submission or I/O errors (may be NULL)
  * @operation: the type of I/O to perform
  * @data: the buffer to read or write (may be NULL)
+ * @size: the I/O amount in bytes
  *
  * The vio is enqueued on a vdo bio queue so that bio submission (which may block) does not block
  * other vdo threads.
@@ -338,7 +339,7 @@ void vdo_submit_data_vio(struct data_vio *data_vio)
  */
 void __submit_metadata_vio(struct vio *vio, physical_block_number_t physical,
                           bio_end_io_t callback, vdo_action_fn error_handler,
-                          blk_opf_t operation, char *data)
+                          blk_opf_t operation, char *data, int size)
 {
        int result;
        struct vdo_completion *completion = &vio->completion;
@@ -349,7 +350,8 @@ void __submit_metadata_vio(struct vio *vio, physical_block_number_t physical,
 
        vdo_reset_completion(completion);
        completion->error_handler = error_handler;
-       result = vio_reset_bio(vio, data, callback, operation | REQ_META, physical);
+       result = vio_reset_bio_with_size(vio, data, size, callback, operation | REQ_META,
+                                        physical);
        if (result != VDO_SUCCESS) {
                continue_vio(vio, result);
                return;

diff --git a/drivers/md/dm-vdo/io-submitter.h b/drivers/md/dm-vdo/io-submitter.h
index 80748699496f2d02f74f58faf6964a6e99034808..3088f11055fdd1c42aee86c9005af34d9afe07da 100644 (file)
--- a/drivers/md/dm-vdo/io-submitter.h
+++ b/drivers/md/dm-vdo/io-submitter.h
@@ -8,6 +8,7 @@
 
 #include <linux/bio.h>
 
+#include "constants.h"
 #include "types.h"
 
 struct io_submitter;
@@ -26,14 +27,25 @@ void vdo_submit_data_vio(struct data_vio *data_vio);
 
 void __submit_metadata_vio(struct vio *vio, physical_block_number_t physical,
                           bio_end_io_t callback, vdo_action_fn error_handler,
-                          blk_opf_t operation, char *data);
+                          blk_opf_t operation, char *data, int size);
 
 static inline void vdo_submit_metadata_vio(struct vio *vio, physical_block_number_t physical,
                                           bio_end_io_t callback, vdo_action_fn error_handler,
                                           blk_opf_t operation)
 {
        __submit_metadata_vio(vio, physical, callback, error_handler,
-                             operation, vio->data);
+                             operation, vio->data, vio->block_count * VDO_BLOCK_SIZE);
+}
+
+static inline void vdo_submit_metadata_vio_with_size(struct vio *vio,
+                                                    physical_block_number_t physical,
+                                                    bio_end_io_t callback,
+                                                    vdo_action_fn error_handler,
+                                                    blk_opf_t operation,
+                                                    int size)
+{
+       __submit_metadata_vio(vio, physical, callback, error_handler,
+                             operation, vio->data, size);
 }
 
 static inline void vdo_submit_flush_vio(struct vio *vio, bio_end_io_t callback,
@@ -41,7 +53,7 @@ static inline void vdo_submit_flush_vio(struct vio *vio, bio_end_io_t callback,
 {
        /* FIXME: Can we just use REQ_OP_FLUSH? */
        __submit_metadata_vio(vio, 0, callback, error_handler,
-                             REQ_OP_WRITE | REQ_PREFLUSH, NULL);
+                             REQ_OP_WRITE | REQ_PREFLUSH, NULL, 0);
 }
 
 #endif /* VDO_IO_SUBMITTER_H */

diff --git a/drivers/md/dm-vdo/types.h b/drivers/md/dm-vdo/types.h
index dbe892b10f2658bad463d8f3fa43ca88d10319f5..cdf36e7d770214f6e565f54c68e2158439c2a739 100644 (file)
--- a/drivers/md/dm-vdo/types.h
+++ b/drivers/md/dm-vdo/types.h
@@ -376,6 +376,9 @@ struct vio {
        /* The size of this vio in blocks */
        unsigned int block_count;
 
+       /* The amount of data to be read or written, in bytes */
+       unsigned int io_size;
+
        /* The data being read or written. */
        char *data;
 

diff --git a/drivers/md/dm-vdo/vio.c b/drivers/md/dm-vdo/vio.c
index f69fb74a238c795dc48e0217330b4de4ebcd2530..e7f4153e55e3c04e91ba8a9530255be05b45a90f 100644 (file)
--- a/drivers/md/dm-vdo/vio.c
+++ b/drivers/md/dm-vdo/vio.c
@@ -188,14 +188,23 @@ void vdo_set_bio_properties(struct bio *bio, struct vio *vio, bio_end_io_t callb
 
 /*
  * Prepares the bio to perform IO with the specified buffer. May only be used on a VDO-allocated
- * bio, as it assumes the bio wraps a 4k buffer that is 4k aligned, but there does not have to be a
- * vio associated with the bio.
+ * bio, as it assumes the bio wraps a 4k-multiple buffer that is 4k aligned, but there does not
+ * have to be a vio associated with the bio.
  */
 int vio_reset_bio(struct vio *vio, char *data, bio_end_io_t callback,
                  blk_opf_t bi_opf, physical_block_number_t pbn)
 {
-       int bvec_count, offset, len, i;
+       return vio_reset_bio_with_size(vio, data, vio->block_count * VDO_BLOCK_SIZE,
+                                      callback, bi_opf, pbn);
+}
+
+int vio_reset_bio_with_size(struct vio *vio, char *data, int size, bio_end_io_t callback,
+                           blk_opf_t bi_opf, physical_block_number_t pbn)
+{
+       int bvec_count, offset, i;
        struct bio *bio = vio->bio;
+       int vio_size = vio->block_count * VDO_BLOCK_SIZE;
+       int remaining;
 
        bio_reset(bio, bio->bi_bdev, bi_opf);
        vdo_set_bio_properties(bio, vio, callback, bi_opf, pbn);
@@ -205,22 +214,21 @@ int vio_reset_bio(struct vio *vio, char *data, bio_end_io_t callback,
        bio->bi_ioprio = 0;
        bio->bi_io_vec = bio->bi_inline_vecs;
        bio->bi_max_vecs = vio->block_count + 1;
-       len = VDO_BLOCK_SIZE * vio->block_count;
+       if (VDO_ASSERT(size <= vio_size, "specified size %d is not greater than allocated %d",
+                      size, vio_size) != VDO_SUCCESS)
+               size = vio_size;
+       vio->io_size = size;
        offset = offset_in_page(data);
-       bvec_count = DIV_ROUND_UP(offset + len, PAGE_SIZE);
+       bvec_count = DIV_ROUND_UP(offset + size, PAGE_SIZE);
+       remaining = size;
 
-       /*
-        * If we knew that data was always on one page, or contiguous pages, we wouldn't need the
-        * loop. But if we're using vmalloc, it's not impossible that the data is in different
-        * pages that can't be merged in bio_add_page...
-        */
-       for (i = 0; (i < bvec_count) && (len > 0); i++) {
+       for (i = 0; (i < bvec_count) && (remaining > 0); i++) {
                struct page *page;
                int bytes_added;
                int bytes = PAGE_SIZE - offset;
 
-               if (bytes > len)
-                       bytes = len;
+               if (bytes > remaining)
+                       bytes = remaining;
 
                page = is_vmalloc_addr(data) ? vmalloc_to_page(data) : virt_to_page(data);
                bytes_added = bio_add_page(bio, page, bytes, offset);
@@ -232,7 +240,7 @@ int vio_reset_bio(struct vio *vio, char *data, bio_end_io_t callback,
                }
 
                data += bytes;
-               len -= bytes;
+               remaining -= bytes;
                offset = 0;
        }
 

diff --git a/drivers/md/dm-vdo/vio.h b/drivers/md/dm-vdo/vio.h
index 8a7e3f72e80b424792f6ca9c5f747c7a838dfa1a..4bfcb21901f149787831ddecfcc3846a1c631ad7 100644 (file)
--- a/drivers/md/dm-vdo/vio.h
+++ b/drivers/md/dm-vdo/vio.h
@@ -125,6 +125,8 @@ void vdo_set_bio_properties(struct bio *bio, struct vio *vio, bio_end_io_t callb
 
 int vio_reset_bio(struct vio *vio, char *data, bio_end_io_t callback,
                  blk_opf_t bi_opf, physical_block_number_t pbn);
+int vio_reset_bio_with_size(struct vio *vio, char *data, int size, bio_end_io_t callback,
+                           blk_opf_t bi_opf, physical_block_number_t pbn);
 
 void update_vio_error_stats(struct vio *vio, const char *format, ...)
        __printf(2, 3);