From f91528955d0094ff2200632661d62ee64019c985 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Tue, 27 Nov 2018 22:32:59 -0500 Subject: iov_iter: reduce code duplication The same combination of csum_partial_copy_nocheck() with csum_add_block() is used in a bunch of places. Add a helper doing just that and use it. Signed-off-by: Al Viro --- lib/iov_iter.c | 54 +++++++++++++++++++++++++++--------------------------- 1 file changed, 27 insertions(+), 27 deletions(-) diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 54c248526b55..621984743268 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -560,13 +560,20 @@ static size_t copy_pipe_to_iter(const void *addr, size_t bytes, return bytes; } +static __wsum csum_and_memcpy(void *to, const void *from, size_t len, + __wsum sum, size_t off) +{ + __wsum next = csum_partial_copy_nocheck(from, to, len, 0); + return csum_block_add(sum, next, off); +} + static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, __wsum *csum, struct iov_iter *i) { struct pipe_inode_info *pipe = i->pipe; size_t n, r; size_t off = 0; - __wsum sum = *csum, next; + __wsum sum = *csum; int idx; if (!sanity(i)) @@ -578,8 +585,7 @@ static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, for ( ; n; idx = next_idx(idx, pipe), r = 0) { size_t chunk = min_t(size_t, n, PAGE_SIZE - r); char *p = kmap_atomic(pipe->bufs[idx].page); - next = csum_partial_copy_nocheck(addr, p + r, chunk, 0); - sum = csum_block_add(sum, next, off); + sum = csum_and_memcpy(p + r, addr, chunk, sum, off); kunmap_atomic(p); i->idx = idx; i->iov_offset = r + chunk; @@ -1400,17 +1406,15 @@ size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, err ? v.iov_len : 0; }), ({ char *p = kmap_atomic(v.bv_page); - next = csum_partial_copy_nocheck(p + v.bv_offset, - (to += v.bv_len) - v.bv_len, - v.bv_len, 0); + sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, + p + v.bv_offset, v.bv_len, + sum, off); kunmap_atomic(p); - sum = csum_block_add(sum, next, off); off += v.bv_len; }),({ - next = csum_partial_copy_nocheck(v.iov_base, - (to += v.iov_len) - v.iov_len, - v.iov_len, 0); - sum = csum_block_add(sum, next, off); + sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, + v.iov_base, v.iov_len, + sum, off); off += v.iov_len; }) ) @@ -1444,17 +1448,15 @@ bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, 0; }), ({ char *p = kmap_atomic(v.bv_page); - next = csum_partial_copy_nocheck(p + v.bv_offset, - (to += v.bv_len) - v.bv_len, - v.bv_len, 0); + sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, + p + v.bv_offset, v.bv_len, + sum, off); kunmap_atomic(p); - sum = csum_block_add(sum, next, off); off += v.bv_len; }),({ - next = csum_partial_copy_nocheck(v.iov_base, - (to += v.iov_len) - v.iov_len, - v.iov_len, 0); - sum = csum_block_add(sum, next, off); + sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, + v.iov_base, v.iov_len, + sum, off); off += v.iov_len; }) ) @@ -1491,17 +1493,15 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum, err ? v.iov_len : 0; }), ({ char *p = kmap_atomic(v.bv_page); - next = csum_partial_copy_nocheck((from += v.bv_len) - v.bv_len, - p + v.bv_offset, - v.bv_len, 0); + sum = csum_and_memcpy(p + v.bv_offset, + (from += v.bv_len) - v.bv_len, + v.bv_len, sum, off); kunmap_atomic(p); - sum = csum_block_add(sum, next, off); off += v.bv_len; }),({ - next = csum_partial_copy_nocheck((from += v.iov_len) - v.iov_len, - v.iov_base, - v.iov_len, 0); - sum = csum_block_add(sum, next, off); + sum = csum_and_memcpy(v.iov_base, + (from += v.iov_len) - v.iov_len, + v.iov_len, sum, off); off += v.iov_len; }) ) -- cgit v1.2.3-59-g8ed1b From 22cb7405fada5305926d9bbcb476c1cd638d2dab Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Fri, 30 Nov 2018 10:33:18 +1100 Subject: VFS: use synchronize_rcu_expedited() in namespace_unlock() The synchronize_rcu() in namespace_unlock() is called every time a filesystem is unmounted. If a great many filesystems are mounted, this can cause a noticable slow-down in, for example, system shutdown. The sequence: mkdir -p /tmp/Mtest/{0..5000} time for i in /tmp/Mtest/*; do mount -t tmpfs tmpfs $i ; done time umount /tmp/Mtest/* on a 4-cpu VM can report 8 seconds to mount the tmpfs filesystems, and 100 seconds to unmount them. Boot the same VM with 1 CPU and it takes 18 seconds to mount the tmpfs filesystems, but only 36 to unmount. If we change the synchronize_rcu() to synchronize_rcu_expedited() the umount time on a 4-cpu VM drop to 0.6 seconds I think this 200-fold speed up is worth the slightly high system impact of using synchronize_rcu_expedited(). Acked-by: Paul E. McKenney (from general rcu perspective) Signed-off-by: NeilBrown Signed-off-by: Al Viro --- fs/namespace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/namespace.c b/fs/namespace.c index 98d27da43304..9cd4fcc0de94 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1360,7 +1360,7 @@ static void namespace_unlock(void) if (likely(hlist_empty(&head))) return; - synchronize_rcu(); + synchronize_rcu_expedited(); group_pin_kill(&head); } -- cgit v1.2.3-59-g8ed1b From a40612ef0ee1e524aafee58d0e5713cf5fdb3d62 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 10 Dec 2018 03:40:11 -0500 Subject: genheaders: %-s had been there since v6; %-*s - since v7 Please, use at least K&R C; printf had been able to left-adjust a field for as long as stdio existed and use of '*' for variable width had been there since v7. Yes, the first edition of K&R didn't cover the latter feature (it slightly predates v7), but you are using a much later feature of the language than that - in K&R C static char *stoupperx(const char *s) { ... } would've been spelled as static char *stoupperx(s) char *s; { ... } While we are at it, the use of strstr() is bogus - it finds the _first_ instance of substring, so it's a lousy fit for checking if a string ends with given suffix... Signed-off-by: Al Viro --- scripts/selinux/genheaders/genheaders.c | 29 +++++++++-------------------- 1 file changed, 9 insertions(+), 20 deletions(-) diff --git a/scripts/selinux/genheaders/genheaders.c b/scripts/selinux/genheaders/genheaders.c index fa48fabcb330..1ceedea847dd 100644 --- a/scripts/selinux/genheaders/genheaders.c +++ b/scripts/selinux/genheaders/genheaders.c @@ -19,8 +19,6 @@ struct security_class_mapping { #include "classmap.h" #include "initial_sid_to_string.h" -#define max(x, y) (((int)(x) > (int)(y)) ? x : y) - const char *progname; static void usage(void) @@ -46,11 +44,9 @@ static char *stoupperx(const char *s) int main(int argc, char *argv[]) { - int i, j, k; + int i, j; int isids_len; FILE *fout; - const char *needle = "SOCKET"; - char *substr; progname = argv[0]; @@ -80,20 +76,14 @@ int main(int argc, char *argv[]) for (i = 0; secclass_map[i].name; i++) { struct security_class_mapping *map = &secclass_map[i]; - fprintf(fout, "#define SECCLASS_%s", map->name); - for (j = 0; j < max(1, 40 - strlen(map->name)); j++) - fprintf(fout, " "); - fprintf(fout, "%2d\n", i+1); + fprintf(fout, "#define SECCLASS_%-39s %2d\n", map->name, i+1); } fprintf(fout, "\n"); for (i = 1; i < isids_len; i++) { const char *s = initial_sid_to_string[i]; - fprintf(fout, "#define SECINITSID_%s", s); - for (j = 0; j < max(1, 40 - strlen(s)); j++) - fprintf(fout, " "); - fprintf(fout, "%2d\n", i); + fprintf(fout, "#define SECINITSID_%-39s %2d\n", s, i); } fprintf(fout, "\n#define SECINITSID_NUM %d\n", i-1); fprintf(fout, "\nstatic inline bool security_is_socket_class(u16 kern_tclass)\n"); @@ -101,9 +91,10 @@ int main(int argc, char *argv[]) fprintf(fout, "\tbool sock = false;\n\n"); fprintf(fout, "\tswitch (kern_tclass) {\n"); for (i = 0; secclass_map[i].name; i++) { + static char s[] = "SOCKET"; struct security_class_mapping *map = &secclass_map[i]; - substr = strstr(map->name, needle); - if (substr && strcmp(substr, needle) == 0) + int len = strlen(map->name), l = sizeof(s) - 1; + if (len >= l && memcmp(map->name + len - l, s, l) == 0) fprintf(fout, "\tcase SECCLASS_%s:\n", map->name); } fprintf(fout, "\t\tsock = true;\n"); @@ -129,17 +120,15 @@ int main(int argc, char *argv[]) for (i = 0; secclass_map[i].name; i++) { struct security_class_mapping *map = &secclass_map[i]; + int len = strlen(map->name); for (j = 0; map->perms[j]; j++) { if (j >= 32) { fprintf(stderr, "Too many permissions to fit into an access vector at (%s, %s).\n", map->name, map->perms[j]); exit(5); } - fprintf(fout, "#define %s__%s", map->name, - map->perms[j]); - for (k = 0; k < max(1, 40 - strlen(map->name) - strlen(map->perms[j])); k++) - fprintf(fout, " "); - fprintf(fout, "0x%08xU\n", (1<name, + 39-len, map->perms[j], 1U< Date: Mon, 10 Dec 2018 16:49:54 +0900 Subject: exec: make prepare_bprm_creds static prepare_bprm_creds is not used outside exec.c, so there's no reason for it to have external linkage. Signed-off-by: Chanho Min Signed-off-by: Al Viro --- fs/exec.c | 2 +- include/linux/binfmts.h | 1 - 2 files changed, 1 insertion(+), 2 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index fc281b738a98..b6c9e5f9f330 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1399,7 +1399,7 @@ EXPORT_SYMBOL(finalize_exec); * Or, if exec fails before, free_bprm() should release ->cred and * and unlock. */ -int prepare_bprm_creds(struct linux_binprm *bprm) +static int prepare_bprm_creds(struct linux_binprm *bprm) { if (mutex_lock_interruptible(¤t->signal->cred_guard_mutex)) return -ERESTARTNOINTR; diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h index e9f5fe69df31..6a9e43d98c3d 100644 --- a/include/linux/binfmts.h +++ b/include/linux/binfmts.h @@ -138,7 +138,6 @@ extern int transfer_args_to_stack(struct linux_binprm *bprm, extern int bprm_change_interp(const char *interp, struct linux_binprm *bprm); extern int copy_strings_kernel(int argc, const char *const *argv, struct linux_binprm *bprm); -extern int prepare_bprm_creds(struct linux_binprm *bprm); extern void install_exec_creds(struct linux_binprm *bprm); extern void set_binfmt(struct linux_binfmt *new); extern ssize_t read_code(struct file *, unsigned long, loff_t, size_t); -- cgit v1.2.3-59-g8ed1b