* [PATCH 1/3] libceph: use "do" in CRC-related Boolean variables
2012-02-29 4:49 [PATCH 0/3] libceph: clean up some code involving CRCs Alex Elder
@ 2012-02-29 4:50 ` Alex Elder
2012-02-29 4:50 ` [PATCH 2/3] libceph: separate CRC calculation from byte swapping Alex Elder
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: Alex Elder @ 2012-02-29 4:50 UTC (permalink / raw)
To: ceph-devel
Change the name (and type) of a few CRC-related Boolean local
variables so they contain the word "do", to distingish their purpose
from variables used for holding an actual CRC value.
Note that in the process of doing this I identified a fairly serious
logic error in write_partial_msg_pages(): the value of "do_crc"
assigned appears to be the opposite of what it should be. No
attempt to fix this is made here; this change preserves the
erroneous behavior. The problem I found is documented here:
http://tracker.newdream.net/issues/2064
Signed-off-by: Alex Elder <elder@dreamhost.com>
---
include/linux/ceph/messenger.h | 2 +-
net/ceph/messenger.c | 40
++++++++++++++++++++--------------------
2 files changed, 21 insertions(+), 21 deletions(-)
diff --git a/include/linux/ceph/messenger.h b/include/linux/ceph/messenger.h
index 5ca0f82..3bff047 100644
--- a/include/linux/ceph/messenger.h
+++ b/include/linux/ceph/messenger.h
@@ -98,7 +98,7 @@ struct ceph_msg {
struct ceph_msg_pos {
int page, page_pos; /* which page; offset in page */
int data_pos; /* offset in data payload */
- int did_page_crc; /* true if we've calculated crc for current page */
+ bool did_page_crc; /* true if we've calculated crc for current page */
};
/* ceph connection fault delay defaults, for exponential backoff */
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index d793b9f..8ac2f33 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -592,7 +592,7 @@ static void prepare_write_message(struct
ceph_connection *con)
else
con->out_msg_pos.page_pos = 0;
con->out_msg_pos.data_pos = 0;
- con->out_msg_pos.did_page_crc = 0;
+ con->out_msg_pos.did_page_crc = false;
con->out_more = 1; /* data + footer will follow */
} else {
/* no, queue up footer too and be done */
@@ -802,7 +802,7 @@ static int write_partial_msg_pages(struct
ceph_connection *con)
struct ceph_msg *msg = con->out_msg;
unsigned data_len = le32_to_cpu(msg->hdr.data_len);
size_t len;
- int crc = con->msgr->nocrc;
+ bool do_crc = con->msgr->nocrc;
int ret;
int total_max_write;
int in_trail = 0;
@@ -840,17 +840,17 @@ static int write_partial_msg_pages(struct
ceph_connection *con)
page = list_first_entry(&msg->trail->head,
struct page, lru);
- if (crc)
+ if (do_crc)
kaddr = kmap(page);
max_write = PAGE_SIZE;
} else if (msg->pages) {
page = msg->pages[con->out_msg_pos.page];
- if (crc)
+ if (do_crc)
kaddr = kmap(page);
} else if (msg->pagelist) {
page = list_first_entry(&msg->pagelist->head,
struct page, lru);
- if (crc)
+ if (do_crc)
kaddr = kmap(page);
#ifdef CONFIG_BLOCK
} else if (msg->bio) {
@@ -859,26 +859,26 @@ static int write_partial_msg_pages(struct
ceph_connection *con)
bv = bio_iovec_idx(msg->bio_iter, msg->bio_seg);
page = bv->bv_page;
page_shift = bv->bv_offset;
- if (crc)
+ if (do_crc)
kaddr = kmap(page) + page_shift;
max_write = bv->bv_len;
#endif
} else {
page = zero_page;
- if (crc)
+ if (do_crc)
kaddr = zero_page_address;
}
len = min_t(int, max_write - con->out_msg_pos.page_pos,
total_max_write);
- if (crc && !con->out_msg_pos.did_page_crc) {
+ if (do_crc && !con->out_msg_pos.did_page_crc) {
void *base = kaddr + con->out_msg_pos.page_pos;
u32 tmpcrc = le32_to_cpu(con->out_msg->footer.data_crc);
BUG_ON(kaddr == NULL);
con->out_msg->footer.data_crc =
cpu_to_le32(crc32c(tmpcrc, base, len));
- con->out_msg_pos.did_page_crc = 1;
+ con->out_msg_pos.did_page_crc = true;
}
ret = kernel_sendpage(con->sock, page,
con->out_msg_pos.page_pos + page_shift,
@@ -886,7 +886,7 @@ static int write_partial_msg_pages(struct
ceph_connection *con)
MSG_DONTWAIT | MSG_NOSIGNAL |
MSG_MORE);
- if (crc &&
+ if (do_crc &&
(msg->pages || msg->pagelist || msg->bio || in_trail))
kunmap(page);
@@ -900,7 +900,7 @@ static int write_partial_msg_pages(struct
ceph_connection *con)
if (ret == len) {
con->out_msg_pos.page_pos = 0;
con->out_msg_pos.page++;
- con->out_msg_pos.did_page_crc = 0;
+ con->out_msg_pos.did_page_crc = false;
if (in_trail)
list_move_tail(&page->lru,
&msg->trail->head);
@@ -917,7 +917,7 @@ static int write_partial_msg_pages(struct
ceph_connection *con)
dout("write_partial_msg_pages %p msg %p done\n", con, msg);
/* prepare and queue up footer, too */
- if (!crc)
+ if (!do_crc)
con->out_msg->footer.flags |= CEPH_MSG_FOOTER_NOCRC;
ceph_con_out_kvec_reset(con);
prepare_write_message_footer(con);
@@ -1554,7 +1554,7 @@ static struct ceph_msg *ceph_alloc_msg(struct
ceph_connection *con,
static int read_partial_message_pages(struct ceph_connection *con,
struct page **pages,
- unsigned data_len, int datacrc)
+ unsigned data_len, bool do_datacrc)
{
void *p;
int ret;
@@ -1567,7 +1567,7 @@ static int read_partial_message_pages(struct
ceph_connection *con,
p = kmap(pages[con->in_msg_pos.page]);
ret = ceph_tcp_recvmsg(con->sock, p + con->in_msg_pos.page_pos,
left);
- if (ret > 0 && datacrc)
+ if (ret > 0 && do_datacrc)
con->in_data_crc =
crc32c(con->in_data_crc,
p + con->in_msg_pos.page_pos, ret);
@@ -1587,7 +1587,7 @@ static int read_partial_message_pages(struct
ceph_connection *con,
#ifdef CONFIG_BLOCK
static int read_partial_message_bio(struct ceph_connection *con,
struct bio **bio_iter, int *bio_seg,
- unsigned data_len, int datacrc)
+ unsigned data_len, bool do_datacrc)
{
struct bio_vec *bv = bio_iovec_idx(*bio_iter, *bio_seg);
void *p;
@@ -1603,7 +1603,7 @@ static int read_partial_message_bio(struct
ceph_connection *con,
ret = ceph_tcp_recvmsg(con->sock, p + con->in_msg_pos.page_pos,
left);
- if (ret > 0 && datacrc)
+ if (ret > 0 && do_datacrc)
con->in_data_crc =
crc32c(con->in_data_crc,
p + con->in_msg_pos.page_pos, ret);
@@ -1630,7 +1630,7 @@ static int read_partial_message(struct
ceph_connection *con)
int ret;
int to, left;
unsigned front_len, middle_len, data_len;
- int datacrc = con->msgr->nocrc;
+ bool do_datacrc = con->msgr->nocrc;
int skip;
u64 seq;
@@ -1741,7 +1741,7 @@ static int read_partial_message(struct
ceph_connection *con)
while (con->in_msg_pos.data_pos < data_len) {
if (m->pages) {
ret = read_partial_message_pages(con, m->pages,
- data_len, datacrc);
+ data_len, do_datacrc);
if (ret <= 0)
return ret;
#ifdef CONFIG_BLOCK
@@ -1749,7 +1749,7 @@ static int read_partial_message(struct
ceph_connection *con)
ret = read_partial_message_bio(con,
&m->bio_iter, &m->bio_seg,
- data_len, datacrc);
+ data_len, do_datacrc);
if (ret <= 0)
return ret;
#endif
@@ -1784,7 +1784,7 @@ static int read_partial_message(struct
ceph_connection *con)
m, con->in_middle_crc, m->footer.middle_crc);
return -EBADMSG;
}
- if (datacrc &&
+ if (do_datacrc &&
(m->footer.flags & CEPH_MSG_FOOTER_NOCRC) == 0 &&
con->in_data_crc != le32_to_cpu(m->footer.data_crc)) {
pr_err("read_partial_message %p data crc %u != exp. %u\n", m,
--
1.7.5.4
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 2/3] libceph: separate CRC calculation from byte swapping
2012-02-29 4:49 [PATCH 0/3] libceph: clean up some code involving CRCs Alex Elder
2012-02-29 4:50 ` [PATCH 1/3] libceph: use "do" in CRC-related Boolean variables Alex Elder
@ 2012-02-29 4:50 ` Alex Elder
2012-02-29 4:50 ` [PATCH 3/3] libceph: do crc calculations outside loop Alex Elder
2012-03-02 21:47 ` [PATCH 0/3] libceph: clean up some code involving CRCs Sage Weil
3 siblings, 0 replies; 6+ messages in thread
From: Alex Elder @ 2012-02-29 4:50 UTC (permalink / raw)
To: ceph-devel
Calculate CRC in a separate step from rearranging the byte order
of the result, to improve clarity and readability.
Use offsetof() to determine the number of bytes to include in the
CRC calculation.
In read_partial_message(), switch which value gets byte-swapped,
since the just-computed CRC is already likely to be in a register.
Signed-off-by: Alex Elder <elder@dreamhost.com>
---
net/ceph/messenger.c | 31 +++++++++++++++++--------------
1 files changed, 17 insertions(+), 14 deletions(-)
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 8ac2f33..1df7e6f 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -518,6 +518,7 @@ static void prepare_write_message_footer(struct
ceph_connection *con)
static void prepare_write_message(struct ceph_connection *con)
{
struct ceph_msg *m;
+ u32 crc;
ceph_con_out_kvec_reset(con);
con->out_kvec_is_msg = true;
@@ -566,17 +567,17 @@ static void prepare_write_message(struct
ceph_connection *con)
m->middle->vec.iov_base);
/* fill in crc (except data pages), footer */
- con->out_msg->hdr.crc =
- cpu_to_le32(crc32c(0, &m->hdr,
- sizeof(m->hdr) - sizeof(m->hdr.crc)));
+ crc = crc32c(0, &m->hdr, offsetof(struct ceph_msg_header, crc));
+ con->out_msg->hdr.crc = cpu_to_le32(crc);
con->out_msg->footer.flags = CEPH_MSG_FOOTER_COMPLETE;
- con->out_msg->footer.front_crc =
- cpu_to_le32(crc32c(0, m->front.iov_base, m->front.iov_len));
- if (m->middle)
- con->out_msg->footer.middle_crc =
- cpu_to_le32(crc32c(0, m->middle->vec.iov_base,
- m->middle->vec.iov_len));
- else
+
+ crc = crc32c(0, m->front.iov_base, m->front.iov_len);
+ con->out_msg->footer.front_crc = cpu_to_le32(crc);
+ if (m->middle) {
+ crc = crc32c(0, m->middle->vec.iov_base,
+ m->middle->vec.iov_len);
+ con->out_msg->footer.middle_crc = cpu_to_le32(crc);
+ } else
con->out_msg->footer.middle_crc = 0;
con->out_msg->footer.data_crc = 0;
dout("prepare_write_message front_crc %u data_crc %u\n",
@@ -872,12 +873,13 @@ static int write_partial_msg_pages(struct
ceph_connection *con)
total_max_write);
if (do_crc && !con->out_msg_pos.did_page_crc) {
+ u32 crc;
void *base = kaddr + con->out_msg_pos.page_pos;
u32 tmpcrc = le32_to_cpu(con->out_msg->footer.data_crc);
BUG_ON(kaddr == NULL);
- con->out_msg->footer.data_crc =
- cpu_to_le32(crc32c(tmpcrc, base, len));
+ crc = crc32c(tmpcrc, base, len);
+ con->out_msg->footer.data_crc = cpu_to_le32(crc);
con->out_msg_pos.did_page_crc = true;
}
ret = kernel_sendpage(con->sock, page,
@@ -1647,8 +1649,9 @@ static int read_partial_message(struct
ceph_connection *con)
con->in_base_pos += ret;
if (con->in_base_pos == sizeof(con->in_hdr)) {
u32 crc = crc32c(0, &con->in_hdr,
- sizeof(con->in_hdr) - sizeof(con->in_hdr.crc));
- if (crc != le32_to_cpu(con->in_hdr.crc)) {
+ offsetof(struct ceph_msg_header, crc));
+
+ if (cpu_to_le32(crc) != con->in_hdr.crc) {
pr_err("read_partial_message bad hdr "
" crc %u != expected %u\n",
crc, con->in_hdr.crc);
--
1.7.5.4
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 3/3] libceph: do crc calculations outside loop
2012-02-29 4:49 [PATCH 0/3] libceph: clean up some code involving CRCs Alex Elder
2012-02-29 4:50 ` [PATCH 1/3] libceph: use "do" in CRC-related Boolean variables Alex Elder
2012-02-29 4:50 ` [PATCH 2/3] libceph: separate CRC calculation from byte swapping Alex Elder
@ 2012-02-29 4:50 ` Alex Elder
2012-03-02 21:47 ` [PATCH 0/3] libceph: clean up some code involving CRCs Sage Weil
3 siblings, 0 replies; 6+ messages in thread
From: Alex Elder @ 2012-02-29 4:50 UTC (permalink / raw)
To: ceph-devel
Move blocks of code out of loops in read_partial_message_section()
and read_partial_message(). They were only was getting called at
the end of the last iteration of the loop anyway.
Signed-off-by: Alex Elder <elder@dreamhost.com>
---
net/ceph/messenger.c | 26 ++++++++++++--------------
1 files changed, 12 insertions(+), 14 deletions(-)
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 1df7e6f..693be64 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -1541,10 +1541,9 @@ static int read_partial_message_section(struct
ceph_connection *con,
if (ret <= 0)
return ret;
section->iov_len += ret;
- if (section->iov_len == sec_len)
- *crc = crc32c(0, section->iov_base,
- section->iov_len);
}
+ if (section->iov_len == sec_len)
+ *crc = crc32c(0, section->iov_base, section->iov_len);
return 1;
}
@@ -1635,6 +1634,7 @@ static int read_partial_message(struct
ceph_connection *con)
bool do_datacrc = con->msgr->nocrc;
int skip;
u64 seq;
+ u32 crc;
dout("read_partial_message con %p msg %p\n", con, m);
@@ -1647,18 +1647,16 @@ static int read_partial_message(struct
ceph_connection *con)
if (ret <= 0)
return ret;
con->in_base_pos += ret;
- if (con->in_base_pos == sizeof(con->in_hdr)) {
- u32 crc = crc32c(0, &con->in_hdr,
- offsetof(struct ceph_msg_header, crc));
-
- if (cpu_to_le32(crc) != con->in_hdr.crc) {
- pr_err("read_partial_message bad hdr "
- " crc %u != expected %u\n",
- crc, con->in_hdr.crc);
- return -EBADMSG;
- }
- }
}
+
+ crc = crc32c(0, &con->in_hdr, offsetof(struct ceph_msg_header, crc));
+ if (cpu_to_le32(crc) != con->in_hdr.crc) {
+ pr_err("read_partial_message bad hdr "
+ " crc %u != expected %u\n",
+ crc, con->in_hdr.crc);
+ return -EBADMSG;
+ }
+
front_len = le32_to_cpu(con->in_hdr.front_len);
if (front_len > CEPH_MSG_MAX_FRONT_LEN)
return -EIO;
--
1.7.5.4
^ permalink raw reply related [flat|nested] 6+ messages in thread