diff options
Diffstat (limited to 'fs/cifs/cifsglob.h')
| -rw-r--r-- | fs/cifs/cifsglob.h | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h index abb831019039..e5cb1941e251 100644 --- a/fs/cifs/cifsglob.h +++ b/fs/cifs/cifsglob.h @@ -213,6 +213,10 @@ struct smb_version_operations { bool (*need_neg)(struct TCP_Server_Info *); /* negotiate to the server */ int (*negotiate)(const unsigned int, struct cifs_ses *); + /* set negotiated write size */ + unsigned int (*negotiate_wsize)(struct cifs_tcon *, struct smb_vol *); + /* set negotiated read size */ + unsigned int (*negotiate_rsize)(struct cifs_tcon *, struct smb_vol *); /* setup smb sessionn */ int (*sess_setup)(const unsigned int, struct cifs_ses *, const struct nls_table *); @@ -516,6 +520,63 @@ get_next_mid(struct TCP_Server_Info *server) } /* + * When the server supports very large reads and writes via POSIX extensions, + * we can allow up to 2^24-1, minus the size of a READ/WRITE_AND_X header, not + * including the RFC1001 length. + * + * Note that this might make for "interesting" allocation problems during + * writeback however as we have to allocate an array of pointers for the + * pages. A 16M write means ~32kb page array with PAGE_CACHE_SIZE == 4096. + * + * For reads, there is a similar problem as we need to allocate an array + * of kvecs to handle the receive, though that should only need to be done + * once. + */ +#define CIFS_MAX_WSIZE ((1<<24) - 1 - sizeof(WRITE_REQ) + 4) +#define CIFS_MAX_RSIZE ((1<<24) - sizeof(READ_RSP) + 4) + +/* + * When the server doesn't allow large posix writes, only allow a rsize/wsize + * of 2^17-1 minus the size of the call header. That allows for a read or + * write up to the maximum size described by RFC1002. + */ +#define CIFS_MAX_RFC1002_WSIZE ((1<<17) - 1 - sizeof(WRITE_REQ) + 4) +#define CIFS_MAX_RFC1002_RSIZE ((1<<17) - 1 - sizeof(READ_RSP) + 4) + +/* + * The default wsize is 1M. find_get_pages seems to return a maximum of 256 + * pages in a single call. With PAGE_CACHE_SIZE == 4k, this means we can fill + * a single wsize request with a single call. + */ +#define CIFS_DEFAULT_IOSIZE (1024 * 1024) + +/* + * Windows only supports a max of 60kb reads and 65535 byte writes. Default to + * those values when posix extensions aren't in force. In actuality here, we + * use 65536 to allow for a write that is a multiple of 4k. Most servers seem + * to be ok with the extra byte even though Windows doesn't send writes that + * are that large. + * + * Citation: + * + * http://blogs.msdn.com/b/openspecification/archive/2009/04/10/smb-maximum-transmit-buffer-size-and-performance-tuning.aspx + */ +#define CIFS_DEFAULT_NON_POSIX_RSIZE (60 * 1024) +#define CIFS_DEFAULT_NON_POSIX_WSIZE (65536) + +/* + * On hosts with high memory, we can't currently support wsize/rsize that are + * larger than we can kmap at once. Cap the rsize/wsize at + * LAST_PKMAP * PAGE_SIZE. We'll never be able to fill a read or write request + * larger than that anyway. + */ +#ifdef CONFIG_HIGHMEM +#define CIFS_KMAP_SIZE_LIMIT (LAST_PKMAP * PAGE_CACHE_SIZE) +#else /* CONFIG_HIGHMEM */ +#define CIFS_KMAP_SIZE_LIMIT (1<<24) +#endif /* CONFIG_HIGHMEM */ + +/* * Macros to allow the TCP_Server_Info->net field and related code to drop out * when CONFIG_NET_NS isn't set. */ |