From: Mathieu Desnoyers Date: Tue, 11 May 2021 17:19:33 +0000 (-0400) Subject: Cleanup: clarify strcpy/strcpy_from_user local variables X-Git-Url: https://git.lttng.org/?p=lttng-modules.git;a=commitdiff_plain;h=e5f1eb9a2a0f516b32966aad52be990b093f24ad Cleanup: clarify strcpy/strcpy_from_user local variables The variable name "bytes_left_in_page" is clearer than "pagecpy". Also the only caller of slow paths always has a 0 pagecpy parameter, so remove that parameter. Also use a "bool" for src_terminated (no functional change). Signed-off-by: Mathieu Desnoyers Change-Id: I38520b8cab54c31dbbb7b9296200b432afb3cee9 --- diff --git a/include/ringbuffer/backend.h b/include/ringbuffer/backend.h index b95a0d38..13f67a4e 100644 --- a/include/ringbuffer/backend.h +++ b/include/ringbuffer/backend.h @@ -215,7 +215,7 @@ void lib_ring_buffer_strcpy(const struct lttng_kernel_ring_buffer_config *config { struct lttng_kernel_ring_buffer_backend *bufb = &ctx->priv.buf->backend; struct channel_backend *chanb = &ctx->priv.chan->backend; - size_t index, pagecpy; + size_t index, bytes_left_in_page; size_t offset = ctx->priv.buf_offset; struct lttng_kernel_ring_buffer_backend_pages *backend_pages; @@ -225,8 +225,8 @@ void lib_ring_buffer_strcpy(const struct lttng_kernel_ring_buffer_config *config lib_ring_buffer_get_backend_pages_from_ctx(config, ctx); offset &= chanb->buf_size - 1; index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; - pagecpy = min_t(size_t, len, (-offset) & ~PAGE_MASK); - if (likely(pagecpy == len)) { + bytes_left_in_page = min_t(size_t, len, (-offset) & ~PAGE_MASK); + if (likely(bytes_left_in_page == len)) { size_t count; count = lib_ring_buffer_do_strcpy(config, @@ -248,7 +248,7 @@ void lib_ring_buffer_strcpy(const struct lttng_kernel_ring_buffer_config *config + (offset & ~PAGE_MASK), '\0', 1); } else { - _lib_ring_buffer_strcpy(bufb, offset, src, len, 0, pad); + _lib_ring_buffer_strcpy(bufb, offset, src, len, pad); } ctx->priv.buf_offset += len; } @@ -404,7 +404,7 @@ void lib_ring_buffer_strcpy_from_user_inatomic(const struct lttng_kernel_ring_bu { struct lttng_kernel_ring_buffer_backend *bufb = &ctx->priv.buf->backend; struct channel_backend *chanb = &ctx->priv.chan->backend; - size_t index, pagecpy; + size_t index, bytes_left_in_page; size_t offset = ctx->priv.buf_offset; struct lttng_kernel_ring_buffer_backend_pages *backend_pages; @@ -414,13 +414,13 @@ void lib_ring_buffer_strcpy_from_user_inatomic(const struct lttng_kernel_ring_bu lib_ring_buffer_get_backend_pages_from_ctx(config, ctx); offset &= chanb->buf_size - 1; index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; - pagecpy = min_t(size_t, len, (-offset) & ~PAGE_MASK); + bytes_left_in_page = min_t(size_t, len, (-offset) & ~PAGE_MASK); if (unlikely(!lttng_access_ok(VERIFY_READ, src, len))) goto fill_buffer; pagefault_disable(); - if (likely(pagecpy == len)) { + if (likely(bytes_left_in_page == len)) { size_t count; count = lib_ring_buffer_do_strcpy_from_user_inatomic(config, @@ -443,7 +443,7 @@ void lib_ring_buffer_strcpy_from_user_inatomic(const struct lttng_kernel_ring_bu '\0', 1); } else { _lib_ring_buffer_strcpy_from_user_inatomic(bufb, offset, src, - len, 0, pad); + len, pad); } pagefault_enable(); ctx->priv.buf_offset += len; diff --git a/include/ringbuffer/backend_internal.h b/include/ringbuffer/backend_internal.h index 20ca39a5..fb60f2ab 100644 --- a/include/ringbuffer/backend_internal.h +++ b/include/ringbuffer/backend_internal.h @@ -46,16 +46,14 @@ extern void _lib_ring_buffer_memset(struct lttng_kernel_ring_buffer_backend *buf size_t offset, int c, size_t len, size_t pagecpy); extern void _lib_ring_buffer_strcpy(struct lttng_kernel_ring_buffer_backend *bufb, - size_t offset, const char *src, size_t len, - size_t pagecpy, int pad); + size_t offset, const char *src, size_t len, int pad); extern void _lib_ring_buffer_pstrcpy(struct lttng_kernel_ring_buffer_backend *bufb, size_t offset, const char *src, size_t len, int pad); extern void _lib_ring_buffer_copy_from_user_inatomic(struct lttng_kernel_ring_buffer_backend *bufb, size_t offset, const void *src, size_t len, size_t pagecpy); extern void _lib_ring_buffer_strcpy_from_user_inatomic(struct lttng_kernel_ring_buffer_backend *bufb, - size_t offset, const char __user *src, size_t len, - size_t pagecpy, int pad); + size_t offset, const char __user *src, size_t len, int pad); extern void _lib_ring_buffer_pstrcpy_from_user_inatomic(struct lttng_kernel_ring_buffer_backend *bufb, size_t offset, const char __user *src, size_t len, int pad); diff --git a/src/lib/ringbuffer/ring_buffer_backend.c b/src/lib/ringbuffer/ring_buffer_backend.c index 76f9b425..cbc931df 100644 --- a/src/lib/ringbuffer/ring_buffer_backend.c +++ b/src/lib/ringbuffer/ring_buffer_backend.c @@ -653,26 +653,20 @@ EXPORT_SYMBOL_GPL(_lib_ring_buffer_memset); * @offset : offset within the buffer * @src : source address * @len : length to write - * @pagecpy : page size copied so far * @pad : character to use for padding */ void _lib_ring_buffer_strcpy(struct lttng_kernel_ring_buffer_backend *bufb, - size_t offset, const char *src, size_t len, - size_t pagecpy, int pad) + size_t offset, const char *src, size_t len, int pad) { struct channel_backend *chanb = &bufb->chan->backend; const struct lttng_kernel_ring_buffer_config *config = &chanb->config; - size_t sbidx, index; + size_t sbidx, index, bytes_left_in_page; struct lttng_kernel_ring_buffer_backend_pages *rpages; unsigned long sb_bindex, id; - int src_terminated = 0; + bool src_terminated = false; CHAN_WARN_ON(chanb, !len); - offset += pagecpy; do { - len -= pagecpy; - if (!src_terminated) - src += pagecpy; sbidx = offset >> chanb->subbuf_size_order; index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; @@ -682,7 +676,7 @@ void _lib_ring_buffer_strcpy(struct lttng_kernel_ring_buffer_backend *bufb, */ CHAN_WARN_ON(chanb, offset >= chanb->buf_size); - pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); + bytes_left_in_page = 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]; @@ -692,8 +686,8 @@ void _lib_ring_buffer_strcpy(struct lttng_kernel_ring_buffer_backend *bufb, if (likely(!src_terminated)) { size_t count, to_copy; - to_copy = pagecpy; - if (pagecpy == len) + to_copy = bytes_left_in_page; + if (bytes_left_in_page == len) to_copy--; /* Final '\0' */ count = lib_ring_buffer_do_strcpy(config, rpages->p[index].virt @@ -705,7 +699,7 @@ void _lib_ring_buffer_strcpy(struct lttng_kernel_ring_buffer_backend *bufb, size_t pad_len = to_copy - count; /* Next pages will have padding */ - src_terminated = 1; + src_terminated = true; lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK), pad, pad_len); @@ -714,15 +708,19 @@ void _lib_ring_buffer_strcpy(struct lttng_kernel_ring_buffer_backend *bufb, } else { size_t pad_len; - pad_len = pagecpy; - if (pagecpy == len) + pad_len = bytes_left_in_page; + if (bytes_left_in_page == len) pad_len--; /* Final '\0' */ lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK), pad, pad_len); offset += pad_len; } - } while (unlikely(len != pagecpy)); + len -= bytes_left_in_page; + if (!src_terminated) + src += bytes_left_in_page; + } while (unlikely(len)); + /* Ending '\0' */ lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK), '\0', 1); @@ -869,7 +867,6 @@ EXPORT_SYMBOL_GPL(_lib_ring_buffer_copy_from_user_inatomic); * @offset : offset within the buffer * @src : source address * @len : length to write - * @pagecpy : page size copied so far * @pad : character to use for padding * * This function deals with userspace pointers, it should never be called @@ -877,21 +874,16 @@ EXPORT_SYMBOL_GPL(_lib_ring_buffer_copy_from_user_inatomic); * previously. */ void _lib_ring_buffer_strcpy_from_user_inatomic(struct lttng_kernel_ring_buffer_backend *bufb, - size_t offset, const char __user *src, size_t len, - size_t pagecpy, int pad) + size_t offset, const char __user *src, size_t len, int pad) { struct channel_backend *chanb = &bufb->chan->backend; const struct lttng_kernel_ring_buffer_config *config = &chanb->config; - size_t sbidx, index; + size_t sbidx, index, bytes_left_in_page; struct lttng_kernel_ring_buffer_backend_pages *rpages; unsigned long sb_bindex, id; - int src_terminated = 0; + bool src_terminated = false; - offset += pagecpy; do { - len -= pagecpy; - if (!src_terminated) - src += pagecpy; sbidx = offset >> chanb->subbuf_size_order; index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; @@ -901,7 +893,7 @@ void _lib_ring_buffer_strcpy_from_user_inatomic(struct lttng_kernel_ring_buffer_ */ CHAN_WARN_ON(chanb, offset >= chanb->buf_size); - pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK)); + bytes_left_in_page = 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]; @@ -911,8 +903,8 @@ void _lib_ring_buffer_strcpy_from_user_inatomic(struct lttng_kernel_ring_buffer_ if (likely(!src_terminated)) { size_t count, to_copy; - to_copy = pagecpy; - if (pagecpy == len) + to_copy = bytes_left_in_page; + if (bytes_left_in_page == len) to_copy--; /* Final '\0' */ count = lib_ring_buffer_do_strcpy_from_user_inatomic(config, rpages->p[index].virt @@ -924,7 +916,7 @@ void _lib_ring_buffer_strcpy_from_user_inatomic(struct lttng_kernel_ring_buffer_ size_t pad_len = to_copy - count; /* Next pages will have padding */ - src_terminated = 1; + src_terminated = true; lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK), pad, pad_len); @@ -933,15 +925,19 @@ void _lib_ring_buffer_strcpy_from_user_inatomic(struct lttng_kernel_ring_buffer_ } else { size_t pad_len; - pad_len = pagecpy; - if (pagecpy == len) + pad_len = bytes_left_in_page; + if (bytes_left_in_page == len) pad_len--; /* Final '\0' */ lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK), pad, pad_len); offset += pad_len; } - } while (unlikely(len != pagecpy)); + len -= bytes_left_in_page; + if (!src_terminated) + src += bytes_left_in_page; + } while (unlikely(len)); + /* Ending '\0' */ lib_ring_buffer_do_memset(rpages->p[index].virt + (offset & ~PAGE_MASK), '\0', 1);