| Message ID | 20201019191928.77845-5-dgilbert@interlog.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3,1/4] sgl_alloc_order: remove 4 GiB limit, sgl_free() warning | expand |
Am 19.10.20 um 21:19 schrieb Douglas Gilbert: > The existing sg_zero_buffer() function is a bit restrictive. > For example protection information (PI) blocks are usually > initialized to 0xff bytes. As its name suggests sgl_memset() > is modelled on memset(). One difference is the type of the > val argument which is u8 rather than int. Plus it returns > the number of bytes (over)written. > > Change implementation of sg_zero_buffer() to call this new > function. > > Signed-off-by: Douglas Gilbert <dgilbert@interlog.com> > --- > include/linux/scatterlist.h | 3 ++ > lib/scatterlist.c | 65 +++++++++++++++++++++++++------------ > 2 files changed, 48 insertions(+), 20 deletions(-) > > diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h > index ae260dc5fedb..a40012c8a4e6 100644 > --- a/include/linux/scatterlist.h > +++ b/include/linux/scatterlist.h > @@ -329,6 +329,9 @@ bool sgl_compare_sgl(struct scatterlist *x_sgl, unsigned int x_nents, off_t x_sk > struct scatterlist *y_sgl, unsigned int y_nents, off_t y_skip, > size_t n_bytes); > > +size_t sgl_memset(struct scatterlist *sgl, unsigned int nents, off_t skip, > + u8 val, size_t n_bytes); > + > /* > * Maximum number of entries that will be allocated in one piece, if > * a list larger than this is required then chaining will be utilized. > diff --git a/lib/scatterlist.c b/lib/scatterlist.c > index 49185536acba..6b430f7293e0 100644 > --- a/lib/scatterlist.c > +++ b/lib/scatterlist.c > @@ -952,26 +952,7 @@ EXPORT_SYMBOL(sg_pcopy_to_buffer); > size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents, > size_t buflen, off_t skip) > { > - unsigned int offset = 0; > - struct sg_mapping_iter miter; > - unsigned int sg_flags = SG_MITER_ATOMIC | SG_MITER_TO_SG; > - > - sg_miter_start(&miter, sgl, nents, sg_flags); > - > - if (!sg_miter_skip(&miter, skip)) > - return false; > - > - while (offset < buflen && sg_miter_next(&miter)) { > - unsigned int len; > - > - len = min(miter.length, buflen - offset); > - memset(miter.addr, 0, len); > - > - offset += len; > - } > - > - sg_miter_stop(&miter); > - return offset; > + return sgl_memset(sgl, nents, skip, 0, buflen); > } > EXPORT_SYMBOL(sg_zero_buffer); > > @@ -1110,3 +1091,47 @@ bool sgl_compare_sgl(struct scatterlist *x_sgl, unsigned int x_nents, off_t x_sk > return equ; > } > EXPORT_SYMBOL(sgl_compare_sgl); > + > +/** > + * sgl_memset - set byte 'val' up to n_bytes times on SG list > + * @sgl: The SG list > + * @nents: Number of SG entries in sgl > + * @skip: Number of bytes to skip before starting > + * @val: byte value to write to sgl > + * @n_bytes: The (maximum) number of bytes to modify > + * > + * Returns: > + * The number of bytes written. > + * > + * Notes: > + * Stops writing if either sgl or n_bytes is exhausted. If n_bytes is > + * set SIZE_MAX then val will be written to each byte until the end > + * of sgl. > + * > + * The notes in sgl_copy_sgl() about large sgl_s _applies here as well. > + * > + **/ > +size_t sgl_memset(struct scatterlist *sgl, unsigned int nents, off_t skip, > + u8 val, size_t n_bytes) > +{ > + size_t offset = 0; > + size_t len; > + struct sg_mapping_iter miter; > + > + if (n_bytes == 0) > + return 0; > + sg_miter_start(&miter, sgl, nents, SG_MITER_ATOMIC | SG_MITER_TO_SG); > + if (!sg_miter_skip(&miter, skip)) > + goto fini; > + > + while ((offset < n_bytes) && sg_miter_next(&miter)) { > + len = min(miter.length, n_bytes - offset); > + memset(miter.addr, val, len); > + offset += len; > + } > +fini: > + sg_miter_stop(&miter); > + return offset; > +} > +EXPORT_SYMBOL(sgl_memset); > + > Reviewed-by: Bodo Stroesser <bostroesser@gmail.com>
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index ae260dc5fedb..a40012c8a4e6 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -329,6 +329,9 @@ bool sgl_compare_sgl(struct scatterlist *x_sgl, unsigned int x_nents, off_t x_sk struct scatterlist *y_sgl, unsigned int y_nents, off_t y_skip, size_t n_bytes); +size_t sgl_memset(struct scatterlist *sgl, unsigned int nents, off_t skip, + u8 val, size_t n_bytes); + /* * Maximum number of entries that will be allocated in one piece, if * a list larger than this is required then chaining will be utilized. diff --git a/lib/scatterlist.c b/lib/scatterlist.c index 49185536acba..6b430f7293e0 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -952,26 +952,7 @@ EXPORT_SYMBOL(sg_pcopy_to_buffer); size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents, size_t buflen, off_t skip) { - unsigned int offset = 0; - struct sg_mapping_iter miter; - unsigned int sg_flags = SG_MITER_ATOMIC | SG_MITER_TO_SG; - - sg_miter_start(&miter, sgl, nents, sg_flags); - - if (!sg_miter_skip(&miter, skip)) - return false; - - while (offset < buflen && sg_miter_next(&miter)) { - unsigned int len; - - len = min(miter.length, buflen - offset); - memset(miter.addr, 0, len); - - offset += len; - } - - sg_miter_stop(&miter); - return offset; + return sgl_memset(sgl, nents, skip, 0, buflen); } EXPORT_SYMBOL(sg_zero_buffer); @@ -1110,3 +1091,47 @@ bool sgl_compare_sgl(struct scatterlist *x_sgl, unsigned int x_nents, off_t x_sk return equ; } EXPORT_SYMBOL(sgl_compare_sgl); + +/** + * sgl_memset - set byte 'val' up to n_bytes times on SG list + * @sgl: The SG list + * @nents: Number of SG entries in sgl + * @skip: Number of bytes to skip before starting + * @val: byte value to write to sgl + * @n_bytes: The (maximum) number of bytes to modify + * + * Returns: + * The number of bytes written. + * + * Notes: + * Stops writing if either sgl or n_bytes is exhausted. If n_bytes is + * set SIZE_MAX then val will be written to each byte until the end + * of sgl. + * + * The notes in sgl_copy_sgl() about large sgl_s _applies here as well. + * + **/ +size_t sgl_memset(struct scatterlist *sgl, unsigned int nents, off_t skip, + u8 val, size_t n_bytes) +{ + size_t offset = 0; + size_t len; + struct sg_mapping_iter miter; + + if (n_bytes == 0) + return 0; + sg_miter_start(&miter, sgl, nents, SG_MITER_ATOMIC | SG_MITER_TO_SG); + if (!sg_miter_skip(&miter, skip)) + goto fini; + + while ((offset < n_bytes) && sg_miter_next(&miter)) { + len = min(miter.length, n_bytes - offset); + memset(miter.addr, val, len); + offset += len; + } +fini: + sg_miter_stop(&miter); + return offset; +} +EXPORT_SYMBOL(sgl_memset); +
The existing sg_zero_buffer() function is a bit restrictive. For example protection information (PI) blocks are usually initialized to 0xff bytes. As its name suggests sgl_memset() is modelled on memset(). One difference is the type of the val argument which is u8 rather than int. Plus it returns the number of bytes (over)written. Change implementation of sg_zero_buffer() to call this new function. Signed-off-by: Douglas Gilbert <dgilbert@interlog.com> --- include/linux/scatterlist.h | 3 ++ lib/scatterlist.c | 65 +++++++++++++++++++++++++------------ 2 files changed, 48 insertions(+), 20 deletions(-)