cifs: use discard iterator to discard unneeded network data more efficiently
[ Upstream commit cf0604a686b11175d8beae60281c4ccc95aaa5c2 ] The iterator, ITER_DISCARD, that can only be used in READ mode and just discards any data copied to it, was added to allow a network filesystem to discard any unwanted data sent by a server. Convert cifs_discard_from_socket() to use this. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com> Stable-dep-of: bedc8f76b353 ("cifs: always initialize struct msghdr smb_msg completely") Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:

committed by
Greg Kroah-Hartman

parent
09867977fc
commit
877231b0e6
@@ -230,6 +230,8 @@ extern unsigned int setup_special_user_owner_ACE(struct cifs_ace *pace);
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extern void dequeue_mid(struct mid_q_entry *mid, bool malformed);
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extern void dequeue_mid(struct mid_q_entry *mid, bool malformed);
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extern int cifs_read_from_socket(struct TCP_Server_Info *server, char *buf,
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extern int cifs_read_from_socket(struct TCP_Server_Info *server, char *buf,
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unsigned int to_read);
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unsigned int to_read);
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extern ssize_t cifs_discard_from_socket(struct TCP_Server_Info *server,
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size_t to_read);
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extern int cifs_read_page_from_socket(struct TCP_Server_Info *server,
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extern int cifs_read_page_from_socket(struct TCP_Server_Info *server,
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struct page *page,
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struct page *page,
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unsigned int page_offset,
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unsigned int page_offset,
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@@ -1451,9 +1451,9 @@ cifs_discard_remaining_data(struct TCP_Server_Info *server)
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while (remaining > 0) {
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while (remaining > 0) {
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int length;
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int length;
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length = cifs_read_from_socket(server, server->bigbuf,
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length = cifs_discard_from_socket(server,
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min_t(unsigned int, remaining,
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min_t(size_t, remaining,
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CIFSMaxBufSize + MAX_HEADER_SIZE(server)));
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CIFSMaxBufSize + MAX_HEADER_SIZE(server)));
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if (length < 0)
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if (length < 0)
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return length;
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return length;
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server->total_read += length;
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server->total_read += length;
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@@ -755,6 +755,23 @@ cifs_read_from_socket(struct TCP_Server_Info *server, char *buf,
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return cifs_readv_from_socket(server, &smb_msg);
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return cifs_readv_from_socket(server, &smb_msg);
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}
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}
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ssize_t
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cifs_discard_from_socket(struct TCP_Server_Info *server, size_t to_read)
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{
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struct msghdr smb_msg;
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/*
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* iov_iter_discard already sets smb_msg.type and count and iov_offset
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* and cifs_readv_from_socket sets msg_control and msg_controllen
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* so little to initialize in struct msghdr
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*/
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smb_msg.msg_name = NULL;
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smb_msg.msg_namelen = 0;
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iov_iter_discard(&smb_msg.msg_iter, READ, to_read);
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return cifs_readv_from_socket(server, &smb_msg);
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}
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int
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int
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cifs_read_page_from_socket(struct TCP_Server_Info *server, struct page *page,
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cifs_read_page_from_socket(struct TCP_Server_Info *server, struct page *page,
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unsigned int page_offset, unsigned int to_read)
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unsigned int page_offset, unsigned int to_read)
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