X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=lib%2Fringbuffer%2Fring_buffer_backend.c;h=8c9d2b7c54e7b583e896fec159349b2336a0fb21;hb=d2bd780e91af600f4b0126b5ff4f560a44a4a32e;hp=a9513d1c07e3072fc9e6f6dcd5418554a1af8255;hpb=88dfd89924114cc8948c300cbd6afd3503ec0b23;p=lttng-modules.git diff --git a/lib/ringbuffer/ring_buffer_backend.c b/lib/ringbuffer/ring_buffer_backend.c index a9513d1c..8c9d2b7c 100644 --- a/lib/ringbuffer/ring_buffer_backend.c +++ b/lib/ringbuffer/ring_buffer_backend.c @@ -1,9 +1,21 @@ /* * ring_buffer_backend.c * - * Copyright (C) 2005-2010 - Mathieu Desnoyers + * Copyright (C) 2005-2012 Mathieu Desnoyers * - * Dual LGPL v2.1/GPL v2 license. + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; only + * version 2.1 of the License. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include @@ -155,7 +167,7 @@ pages_error: int lib_ring_buffer_backend_create(struct lib_ring_buffer_backend *bufb, struct channel_backend *chanb, int cpu) { - const struct lib_ring_buffer_config *config = chanb->config; + const struct lib_ring_buffer_config *config = &chanb->config; bufb->chan = container_of(chanb, struct channel, backend); bufb->cpu = cpu; @@ -187,7 +199,7 @@ void lib_ring_buffer_backend_free(struct lib_ring_buffer_backend *bufb) void lib_ring_buffer_backend_reset(struct lib_ring_buffer_backend *bufb) { struct channel_backend *chanb = &bufb->chan->backend; - const struct lib_ring_buffer_config *config = chanb->config; + const struct lib_ring_buffer_config *config = &chanb->config; unsigned long num_subbuf_alloc; unsigned int i; @@ -221,7 +233,7 @@ void lib_ring_buffer_backend_reset(struct lib_ring_buffer_backend *bufb) void channel_backend_reset(struct channel_backend *chanb) { struct channel *chan = container_of(chanb, struct channel, backend); - const struct lib_ring_buffer_config *config = chanb->config; + const struct lib_ring_buffer_config *config = &chanb->config; /* * Don't reset buf_size, subbuf_size, subbuf_size_order, @@ -241,14 +253,14 @@ void channel_backend_reset(struct channel_backend *chanb) * Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD) */ static -int __cpuinit lib_ring_buffer_cpu_hp_callback(struct notifier_block *nb, +int lib_ring_buffer_cpu_hp_callback(struct notifier_block *nb, unsigned long action, void *hcpu) { unsigned int cpu = (unsigned long)hcpu; struct channel_backend *chanb = container_of(nb, struct channel_backend, cpu_hp_notifier); - const struct lib_ring_buffer_config *config = chanb->config; + const struct lib_ring_buffer_config *config = &chanb->config; struct lib_ring_buffer *buf; int ret; @@ -307,18 +319,18 @@ int channel_backend_init(struct channel_backend *chanb, if (!name) return -EPERM; - if (!(subbuf_size && num_subbuf)) - return -EPERM; - /* Check that the subbuffer size is larger than a page. */ if (subbuf_size < PAGE_SIZE) return -EINVAL; /* - * Make sure the number of subbuffers and subbuffer size are power of 2. + * Make sure the number of subbuffers and subbuffer size are + * power of 2 and nonzero. */ - CHAN_WARN_ON(chanb, hweight32(subbuf_size) != 1); - CHAN_WARN_ON(chanb, hweight32(num_subbuf) != 1); + if (!subbuf_size || (subbuf_size & (subbuf_size - 1))) + return -EINVAL; + if (!num_subbuf || (num_subbuf & (num_subbuf - 1))) + return -EINVAL; ret = subbuffer_id_check_index(config, num_subbuf); if (ret) @@ -334,7 +346,7 @@ int channel_backend_init(struct channel_backend *chanb, (config->mode == RING_BUFFER_OVERWRITE) ? 1 : 0; chanb->num_subbuf = num_subbuf; strlcpy(chanb->name, name, NAME_MAX); - chanb->config = config; + memcpy(&chanb->config, config, sizeof(chanb->config)); if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { if (!zalloc_cpumask_var(&chanb->cpumask, GFP_KERNEL)) @@ -421,7 +433,7 @@ free_cpumask: */ void channel_backend_unregister_notifiers(struct channel_backend *chanb) { - const struct lib_ring_buffer_config *config = chanb->config; + const struct lib_ring_buffer_config *config = &chanb->config; if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) unregister_hotcpu_notifier(&chanb->cpu_hp_notifier); @@ -435,7 +447,7 @@ void channel_backend_unregister_notifiers(struct channel_backend *chanb) */ void channel_backend_free(struct channel_backend *chanb) { - const struct lib_ring_buffer_config *config = chanb->config; + const struct lib_ring_buffer_config *config = &chanb->config; unsigned int i; if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { @@ -469,7 +481,7 @@ void _lib_ring_buffer_write(struct lib_ring_buffer_backend *bufb, size_t offset, const void *src, size_t len, ssize_t pagecpy) { struct channel_backend *chanb = &bufb->chan->backend; - const struct lib_ring_buffer_config *config = chanb->config; + const struct lib_ring_buffer_config *config = &chanb->config; size_t sbidx, index; struct lib_ring_buffer_backend_pages *rpages; unsigned long sb_bindex, id; @@ -501,6 +513,107 @@ void _lib_ring_buffer_write(struct lib_ring_buffer_backend *bufb, size_t offset, } EXPORT_SYMBOL_GPL(_lib_ring_buffer_write); + +/** + * lib_ring_buffer_memset - write len bytes of c to a ring_buffer buffer. + * @bufb : buffer backend + * @offset : offset within the buffer + * @c : the byte to write + * @len : length to write + * @pagecpy : page size copied so far + */ +void _lib_ring_buffer_memset(struct lib_ring_buffer_backend *bufb, + size_t offset, + int c, size_t len, ssize_t pagecpy) +{ + struct channel_backend *chanb = &bufb->chan->backend; + const struct lib_ring_buffer_config *config = &chanb->config; + size_t sbidx, index; + struct lib_ring_buffer_backend_pages *rpages; + unsigned long sb_bindex, id; + + do { + len -= pagecpy; + offset += pagecpy; + sbidx = offset >> chanb->subbuf_size_order; + index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; + + /* + * Underlying layer should never ask for writes across + * subbuffers. + */ + CHAN_WARN_ON(chanb, offset >= chanb->buf_size); + + pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); + id = bufb->buf_wsb[sbidx].id; + sb_bindex = subbuffer_id_get_index(config, id); + rpages = bufb->array[sb_bindex]; + CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE + && subbuffer_id_is_noref(config, id)); + lib_ring_buffer_do_memset(rpages->p[index].virt + + (offset & ~PAGE_MASK), + c, pagecpy); + } while (unlikely(len != pagecpy)); +} +EXPORT_SYMBOL_GPL(_lib_ring_buffer_memset); + + +/** + * lib_ring_buffer_copy_from_user_inatomic - write user data to a ring_buffer buffer. + * @bufb : buffer backend + * @offset : offset within the buffer + * @src : source address + * @len : length to write + * @pagecpy : page size copied so far + * + * This function deals with userspace pointers, it should never be called + * directly without having the src pointer checked with access_ok() + * previously. + */ +void _lib_ring_buffer_copy_from_user_inatomic(struct lib_ring_buffer_backend *bufb, + size_t offset, + const void __user *src, size_t len, + ssize_t pagecpy) +{ + struct channel_backend *chanb = &bufb->chan->backend; + const struct lib_ring_buffer_config *config = &chanb->config; + size_t sbidx, index; + struct lib_ring_buffer_backend_pages *rpages; + unsigned long sb_bindex, id; + int ret; + + do { + len -= pagecpy; + src += pagecpy; + offset += pagecpy; + sbidx = offset >> chanb->subbuf_size_order; + index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; + + /* + * Underlying layer should never ask for writes across + * subbuffers. + */ + CHAN_WARN_ON(chanb, offset >= chanb->buf_size); + + pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); + id = bufb->buf_wsb[sbidx].id; + sb_bindex = subbuffer_id_get_index(config, id); + rpages = bufb->array[sb_bindex]; + CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE + && subbuffer_id_is_noref(config, id)); + ret = lib_ring_buffer_do_copy_from_user_inatomic(rpages->p[index].virt + + (offset & ~PAGE_MASK), + src, pagecpy) != 0; + if (ret > 0) { + offset += (pagecpy - ret); + len -= (pagecpy - ret); + _lib_ring_buffer_memset(bufb, offset, 0, len, 0); + break; /* stop copy */ + } + } while (unlikely(len != pagecpy)); +} +EXPORT_SYMBOL_GPL(_lib_ring_buffer_copy_from_user_inatomic); + /** * lib_ring_buffer_read - read data from ring_buffer_buffer. * @bufb : buffer backend @@ -515,7 +628,7 @@ size_t lib_ring_buffer_read(struct lib_ring_buffer_backend *bufb, size_t offset, void *dest, size_t len) { struct channel_backend *chanb = &bufb->chan->backend; - const struct lib_ring_buffer_config *config = chanb->config; + const struct lib_ring_buffer_config *config = &chanb->config; size_t index; ssize_t pagecpy, orig_len; struct lib_ring_buffer_backend_pages *rpages; @@ -567,7 +680,7 @@ int __lib_ring_buffer_copy_to_user(struct lib_ring_buffer_backend *bufb, size_t offset, void __user *dest, size_t len) { struct channel_backend *chanb = &bufb->chan->backend; - const struct lib_ring_buffer_config *config = chanb->config; + const struct lib_ring_buffer_config *config = &chanb->config; size_t index; ssize_t pagecpy; struct lib_ring_buffer_backend_pages *rpages; @@ -611,14 +724,15 @@ EXPORT_SYMBOL_GPL(__lib_ring_buffer_copy_to_user); * @dest : destination address * @len : destination's length * - * return string's length + * Return string's length, or -EINVAL on error. * Should be protected by get_subbuf/put_subbuf. + * Destination length should be at least 1 to hold '\0'. */ int lib_ring_buffer_read_cstr(struct lib_ring_buffer_backend *bufb, size_t offset, void *dest, size_t len) { struct channel_backend *chanb = &bufb->chan->backend; - const struct lib_ring_buffer_config *config = chanb->config; + const struct lib_ring_buffer_config *config = &chanb->config; size_t index; ssize_t pagecpy, pagelen, strpagelen, orig_offset; char *str; @@ -628,6 +742,8 @@ int lib_ring_buffer_read_cstr(struct lib_ring_buffer_backend *bufb, size_t offse offset &= chanb->buf_size - 1; index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; orig_offset = offset; + if (unlikely(!len)) + return -EINVAL; for (;;) { id = bufb->buf_rsb.id; sb_bindex = subbuffer_id_get_index(config, id); @@ -676,7 +792,7 @@ struct page **lib_ring_buffer_read_get_page(struct lib_ring_buffer_backend *bufb size_t index; struct lib_ring_buffer_backend_pages *rpages; struct channel_backend *chanb = &bufb->chan->backend; - const struct lib_ring_buffer_config *config = chanb->config; + const struct lib_ring_buffer_config *config = &chanb->config; unsigned long sb_bindex, id; offset &= chanb->buf_size - 1; @@ -707,7 +823,7 @@ void *lib_ring_buffer_read_offset_address(struct lib_ring_buffer_backend *bufb, size_t index; struct lib_ring_buffer_backend_pages *rpages; struct channel_backend *chanb = &bufb->chan->backend; - const struct lib_ring_buffer_config *config = chanb->config; + const struct lib_ring_buffer_config *config = &chanb->config; unsigned long sb_bindex, id; offset &= chanb->buf_size - 1; @@ -737,7 +853,7 @@ void *lib_ring_buffer_offset_address(struct lib_ring_buffer_backend *bufb, size_t sbidx, index; struct lib_ring_buffer_backend_pages *rpages; struct channel_backend *chanb = &bufb->chan->backend; - const struct lib_ring_buffer_config *config = chanb->config; + const struct lib_ring_buffer_config *config = &chanb->config; unsigned long sb_bindex, id; offset &= chanb->buf_size - 1;