libceph: preallocate message data items

Currently message data items are allocated with ceph_msg_data_create()
in setup_request_data() inside send_request().  send_request() has never
been allowed to fail, so each allocation is followed by a BUG_ON:

  data = ceph_msg_data_create(...);
  BUG_ON(!data);

It's been this way since support for multiple message data items was
added in commit 6644ed7b7e ("libceph: make message data be a pointer")
in 3.10.

There is no reason to delay the allocation of message data items until
the last possible moment and we certainly don't need a linked list of
them as they are only ever appended to the end and never erased.  Make
ceph_msg_new2() take max_data_items and adapt the rest of the code.

Reported-by: Jerry Lee <leisurelysw24@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
This commit is contained in:
Ilya Dryomov
2018-10-15 17:38:23 +02:00
parent 26f887e0a3
commit 0d9c1ab3be
6 changed files with 157 additions and 115 deletions

View File

@@ -82,22 +82,6 @@ enum ceph_msg_data_type {
CEPH_MSG_DATA_BVECS, /* data source/destination is a bio_vec array */
};
static __inline__ bool ceph_msg_data_type_valid(enum ceph_msg_data_type type)
{
switch (type) {
case CEPH_MSG_DATA_NONE:
case CEPH_MSG_DATA_PAGES:
case CEPH_MSG_DATA_PAGELIST:
#ifdef CONFIG_BLOCK
case CEPH_MSG_DATA_BIO:
#endif /* CONFIG_BLOCK */
case CEPH_MSG_DATA_BVECS:
return true;
default:
return false;
}
}
#ifdef CONFIG_BLOCK
struct ceph_bio_iter {
@@ -181,7 +165,6 @@ struct ceph_bvec_iter {
} while (0)
struct ceph_msg_data {
struct list_head links; /* ceph_msg->data */
enum ceph_msg_data_type type;
union {
#ifdef CONFIG_BLOCK
@@ -202,7 +185,6 @@ struct ceph_msg_data {
struct ceph_msg_data_cursor {
size_t total_resid; /* across all data items */
struct list_head *data_head; /* = &ceph_msg->data */
struct ceph_msg_data *data; /* current data item */
size_t resid; /* bytes not yet consumed */
@@ -240,7 +222,9 @@ struct ceph_msg {
struct ceph_buffer *middle;
size_t data_length;
struct list_head data;
struct ceph_msg_data *data;
int num_data_items;
int max_data_items;
struct ceph_msg_data_cursor cursor;
struct ceph_connection *con;
@@ -381,6 +365,8 @@ void ceph_msg_data_add_bio(struct ceph_msg *msg, struct ceph_bio_iter *bio_pos,
void ceph_msg_data_add_bvecs(struct ceph_msg *msg,
struct ceph_bvec_iter *bvec_pos);
struct ceph_msg *ceph_msg_new2(int type, int front_len, int max_data_items,
gfp_t flags, bool can_fail);
extern struct ceph_msg *ceph_msg_new(int type, int front_len, gfp_t flags,
bool can_fail);