X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=include%2Fringbuffer%2Fbackend.h;h=13f67a4ea8c51e48f8832ff1813931a772997442;hb=e5f1eb9a2a0f516b32966aad52be990b093f24ad;hp=be72d769520337425fe53996e16295b0b646700e;hpb=737afda6fdb357a8fbbf0a7172c06ab3a597bba6;p=lttng-modules.git diff --git a/include/ringbuffer/backend.h b/include/ringbuffer/backend.h index be72d769..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 +248,69 @@ 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; +} + +/** + * lib_ring_buffer_pstrcpy - write kernel C-string (input) to a buffer backend P-string + * @config : ring buffer instance configuration + * @ctx: ring buffer context. (input arguments only) + * @src : source pointer to copy from + * @len : length of data to copy + * @pad : character to use for padding + * + * This function copies up to @len bytes of data from a source pointer + * to a Pascal String into the buffer backend. If a terminating '\0' + * character is found in @src before @len characters are copied, pad the + * buffer with @pad characters (e.g. '\0'). + * + * The length of the pascal strings in the ring buffer is explicit: it + * is either the array or sequence length. + */ +static inline +void lib_ring_buffer_pstrcpy(const struct lttng_kernel_ring_buffer_config *config, + struct lttng_kernel_ring_buffer_ctx *ctx, + const char *src, size_t len, char pad) + __attribute__((always_inline)); +static inline +void lib_ring_buffer_pstrcpy(const struct lttng_kernel_ring_buffer_config *config, + struct lttng_kernel_ring_buffer_ctx *ctx, + const char *src, size_t len, char pad) +{ + struct lttng_kernel_ring_buffer_backend *bufb = &ctx->priv.buf->backend; + struct channel_backend *chanb = &ctx->priv.chan->backend; + size_t index, bytes_left_in_page; + size_t offset = ctx->priv.buf_offset; + struct lttng_kernel_ring_buffer_backend_pages *backend_pages; + + if (unlikely(!len)) + return; + backend_pages = + lib_ring_buffer_get_backend_pages_from_ctx(config, ctx); + offset &= chanb->buf_size - 1; + index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; + 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, + backend_pages->p[index].virt + + (offset & ~PAGE_MASK), + src, len); + offset += count; + /* Padding */ + if (unlikely(count < len)) { + size_t pad_len = len - count; + + lib_ring_buffer_do_memset(backend_pages->p[index].virt + + (offset & ~PAGE_MASK), + pad, pad_len); + offset += pad_len; + } + } else { + _lib_ring_buffer_pstrcpy(bufb, offset, src, len, pad); } ctx->priv.buf_offset += len; } @@ -342,7 +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; @@ -352,13 +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, @@ -381,7 +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; @@ -399,6 +461,84 @@ fill_buffer: ctx->priv.buf_offset += len; } +/** + * lib_ring_buffer_pstrcpy_from_user_inatomic - write user-space C-string (input) to a buffer backend P-string + * @config : ring buffer instance configuration + * @ctx: ring buffer context. (input arguments only) + * @src : source pointer to copy from + * @len : length of data to copy + * @pad : character to use for padding + * + * This function copies up to @len bytes of data from a source pointer + * to a Pascal String into the buffer backend. If a terminating '\0' + * character is found in @src before @len characters are copied, pad the + * buffer with @pad characters (e.g. '\0'). + * + * The length of the pascal strings in the ring buffer is explicit: it + * is either the array or sequence length. + */ +static inline +void lib_ring_buffer_pstrcpy_from_user_inatomic(const struct lttng_kernel_ring_buffer_config *config, + struct lttng_kernel_ring_buffer_ctx *ctx, + const char __user *src, size_t len, char pad) + __attribute__((always_inline)); +static inline +void lib_ring_buffer_pstrcpy_from_user_inatomic(const struct lttng_kernel_ring_buffer_config *config, + struct lttng_kernel_ring_buffer_ctx *ctx, + const char __user *src, size_t len, char pad) +{ + struct lttng_kernel_ring_buffer_backend *bufb = &ctx->priv.buf->backend; + struct channel_backend *chanb = &ctx->priv.chan->backend; + size_t index, bytes_left_in_page; + size_t offset = ctx->priv.buf_offset; + struct lttng_kernel_ring_buffer_backend_pages *backend_pages; + + if (unlikely(!len)) + return; + backend_pages = + lib_ring_buffer_get_backend_pages_from_ctx(config, ctx); + offset &= chanb->buf_size - 1; + index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT; + 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(bytes_left_in_page == len)) { + size_t count; + + count = lib_ring_buffer_do_strcpy_from_user_inatomic(config, + backend_pages->p[index].virt + + (offset & ~PAGE_MASK), + src, len); + offset += count; + /* Padding */ + if (unlikely(count < len)) { + size_t pad_len = len - count; + + lib_ring_buffer_do_memset(backend_pages->p[index].virt + + (offset & ~PAGE_MASK), + pad, pad_len); + offset += pad_len; + } + } else { + _lib_ring_buffer_pstrcpy_from_user_inatomic(bufb, offset, src, len, pad); + } + ctx->priv.buf_offset += len; + pagefault_enable(); + + return; + +fill_buffer: + /* + * In the error path we call the slow path version to avoid + * the pollution of static inline code. + */ + _lib_ring_buffer_memset(bufb, offset, pad, len, 0); + ctx->priv.buf_offset += len; +} + /* * This accessor counts the number of unread records in a buffer. * It only provides a consistent value if no reads not writes are performed