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cifs: move buffer pointers into TCP_Server_Info
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We have several functions that need to access these pointers. Currently
that's done with a lot of double pointer passing. Instead, move them
into the TCP_Server_Info and simplify the handling.

Reviewed-and-Tested-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
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Jeff Layton committed Oct 19, 2011
1 parent ffc00e2 commit 2a37ef9
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Showing 2 changed files with 50 additions and 55 deletions.
4 changes: 4 additions & 0 deletions fs/cifs/cifsglob.h
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Original file line number Diff line number Diff line change
Expand Up @@ -291,9 +291,13 @@ struct TCP_Server_Info {
bool sec_kerberosu2u; /* supports U2U Kerberos */
bool sec_kerberos; /* supports plain Kerberos */
bool sec_mskerberos; /* supports legacy MS Kerberos */
bool large_buf; /* is current buffer large? */
struct delayed_work echo; /* echo ping workqueue job */
struct kvec *iov; /* reusable kvec array for receives */
unsigned int nr_iov; /* number of kvecs in array */
char *smallbuf; /* pointer to current "small" buffer */
char *bigbuf; /* pointer to current "big" buffer */
unsigned int total_read; /* total amount of data read in this pass */
#ifdef CONFIG_CIFS_FSCACHE
struct fscache_cookie *fscache; /* client index cache cookie */
#endif
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101 changes: 46 additions & 55 deletions fs/cifs/connect.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -320,27 +320,24 @@ cifs_echo_request(struct work_struct *work)
}

static bool
allocate_buffers(char **bigbuf, char **smallbuf, unsigned int size,
bool is_large_buf)
allocate_buffers(struct TCP_Server_Info *server)
{
char *bbuf = *bigbuf, *sbuf = *smallbuf;

if (bbuf == NULL) {
bbuf = (char *)cifs_buf_get();
if (!bbuf) {
if (!server->bigbuf) {
server->bigbuf = (char *)cifs_buf_get();
if (!server->bigbuf) {
cERROR(1, "No memory for large SMB response");
msleep(3000);
/* retry will check if exiting */
return false;
}
} else if (is_large_buf) {
} else if (server->large_buf) {
/* we are reusing a dirty large buf, clear its start */
memset(bbuf, 0, size);
memset(server->bigbuf, 0, sizeof(struct smb_hdr));
}

if (sbuf == NULL) {
sbuf = (char *)cifs_small_buf_get();
if (!sbuf) {
if (!server->smallbuf) {
server->smallbuf = (char *)cifs_small_buf_get();
if (!server->smallbuf) {
cERROR(1, "No memory for SMB response");
msleep(1000);
/* retry will check if exiting */
Expand All @@ -349,12 +346,9 @@ allocate_buffers(char **bigbuf, char **smallbuf, unsigned int size,
/* beginning of smb buffer is cleared in our buf_get */
} else {
/* if existing small buf clear beginning */
memset(sbuf, 0, size);
memset(server->smallbuf, 0, sizeof(struct smb_hdr));
}

*bigbuf = bbuf;
*smallbuf = sbuf;

return true;
}

Expand Down Expand Up @@ -576,7 +570,7 @@ dequeue_mid(struct mid_q_entry *mid, int malformed)

static struct mid_q_entry *
find_cifs_mid(struct TCP_Server_Info *server, struct smb_hdr *buf,
int malformed, bool is_large_buf, char **bigbuf)
int malformed)
{
struct mid_q_entry *mid = NULL;

Expand All @@ -596,19 +590,27 @@ find_cifs_mid(struct TCP_Server_Info *server, struct smb_hdr *buf,
mid->multiEnd = true;
goto multi_t2_fnd;
}
if (!is_large_buf) {
if (!server->large_buf) {
/*FIXME: switch to already allocated largebuf?*/
cERROR(1, "1st trans2 resp needs bigbuf");
} else {
/* Have first buffer */
mid->resp_buf = buf;
mid->largeBuf = true;
*bigbuf = NULL;
server->bigbuf = NULL;
}
return mid;
}
mid->resp_buf = buf;
mid->largeBuf = is_large_buf;
mid->largeBuf = server->large_buf;
/* Was previous buf put in mpx struct for multi-rsp? */
if (!mid->multiRsp) {
/* smb buffer will be freed by user thread */
if (server->large_buf)
server->bigbuf = NULL;
else
server->smallbuf = NULL;
}
multi_t2_fnd:
dequeue_mid(mid, malformed);
return mid;
Expand Down Expand Up @@ -715,12 +717,11 @@ cifs_demultiplex_thread(void *p)
{
int length;
struct TCP_Server_Info *server = p;
unsigned int pdu_length, total_read;
char *buf = NULL, *bigbuf = NULL, *smallbuf = NULL;
unsigned int pdu_length;
char *buf = NULL;
struct smb_hdr *smb_buffer = NULL;
struct task_struct *task_to_wake = NULL;
struct mid_q_entry *mid_entry;
bool isLargeBuf = false;

current->flags |= PF_MEMALLOC;
cFYI(1, "Demultiplex PID: %d", task_pid_nr(current));
Expand All @@ -735,19 +736,18 @@ cifs_demultiplex_thread(void *p)
if (try_to_freeze())
continue;

if (!allocate_buffers(&bigbuf, &smallbuf,
sizeof(struct smb_hdr), isLargeBuf))
if (!allocate_buffers(server))
continue;

isLargeBuf = false;
smb_buffer = (struct smb_hdr *)smallbuf;
buf = smallbuf;
server->large_buf = false;
smb_buffer = (struct smb_hdr *)server->smallbuf;
buf = server->smallbuf;
pdu_length = 4; /* enough to get RFC1001 header */

length = read_from_socket(server, buf, pdu_length);
if (length < 0)
continue;
total_read = length;
server->total_read = length;

/*
* The right amount was read from socket - 4 bytes,
Expand All @@ -773,7 +773,7 @@ cifs_demultiplex_thread(void *p)
sizeof(struct smb_hdr) - 1 - 4);
if (length < 0)
continue;
total_read += length;
server->total_read += length;

if (pdu_length > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) {
cERROR(1, "SMB response too long (%u bytes)",
Expand All @@ -785,10 +785,11 @@ cifs_demultiplex_thread(void *p)

/* else length ok */
if (pdu_length > MAX_CIFS_SMALL_BUFFER_SIZE - 4) {
isLargeBuf = true;
memcpy(bigbuf, smallbuf, total_read);
smb_buffer = (struct smb_hdr *)bigbuf;
buf = bigbuf;
server->large_buf = true;
memcpy(server->bigbuf, server->smallbuf,
server->total_read);
smb_buffer = (struct smb_hdr *)server->bigbuf;
buf = server->bigbuf;
}

/* now read the rest */
Expand All @@ -797,9 +798,9 @@ cifs_demultiplex_thread(void *p)
pdu_length - sizeof(struct smb_hdr) + 1 + 4);
if (length < 0)
continue;
total_read += length;
server->total_read += length;

dump_smb(smb_buffer, total_read);
dump_smb(smb_buffer, server->total_read);

/*
* We know that we received enough to get to the MID as we
Expand All @@ -810,28 +811,18 @@ cifs_demultiplex_thread(void *p)
* 48 bytes is enough to display the header and a little bit
* into the payload for debugging purposes.
*/
length = checkSMB(smb_buffer, smb_buffer->Mid, total_read);
length = checkSMB(smb_buffer, smb_buffer->Mid,
server->total_read);
if (length != 0)
cifs_dump_mem("Bad SMB: ", buf,
min_t(unsigned int, total_read, 48));
min_t(unsigned int, server->total_read, 48));

server->lstrp = jiffies;

mid_entry = find_cifs_mid(server, smb_buffer, length,
isLargeBuf, &bigbuf);
mid_entry = find_cifs_mid(server, smb_buffer, length);
if (mid_entry != NULL) {
if (mid_entry->multiRsp && !mid_entry->multiEnd)
continue;

/* Was previous buf put in mpx struct for multi-rsp? */
if (!mid_entry->multiRsp) {
/* smb buffer will be freed by user thread */
if (isLargeBuf)
bigbuf = NULL;
else
smallbuf = NULL;
}
mid_entry->callback(mid_entry);
if (!mid_entry->multiRsp || mid_entry->multiEnd)
mid_entry->callback(mid_entry);
} else if (length != 0) {
/* response sanity checks failed */
continue;
Expand All @@ -849,9 +840,9 @@ cifs_demultiplex_thread(void *p)
} /* end while !EXITING */

/* buffer usually freed in free_mid - need to free it here on exit */
cifs_buf_release(bigbuf);
if (smallbuf) /* no sense logging a debug message if NULL */
cifs_small_buf_release(smallbuf);
cifs_buf_release(server->bigbuf);
if (server->smallbuf) /* no sense logging a debug message if NULL */
cifs_small_buf_release(server->smallbuf);

task_to_wake = xchg(&server->tsk, NULL);
clean_demultiplex_info(server);
Expand Down

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