Messages in this thread Patch in this message | | | Date | Tue, 27 Jan 2015 20:36:25 -0300 | From | Ezequiel Garcia <> | Subject | Re: [PATCH 1/2 v2] UBI: Add initial support for scatter gather |
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On 01/10/2015 06:52 PM, Richard Weinberger wrote: > Adds a new set of functions to deal with scatter gather. > ubi_eba_read_leb_sg() will read from a LEB into a scatter gather list. > The new data structure struct ubi_sgl will be used within UBI to > hold the scatter gather list itself and metadata to have a cursor > within the list. > > Signed-off-by: Richard Weinberger <richard@nod.at> > Tested-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Three nitpicks below, and my
Reviewed-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
> --- > drivers/mtd/ubi/eba.c | 56 +++++++++++++++++++++++++++++ > drivers/mtd/ubi/kapi.c | 95 +++++++++++++++++++++++++++++++++++++++++-------- > drivers/mtd/ubi/ubi.h | 3 ++ > include/linux/mtd/ubi.h | 46 ++++++++++++++++++++++++ > 4 files changed, 185 insertions(+), 15 deletions(-) > > diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c > index b698534..0aaf707 100644 > --- a/drivers/mtd/ubi/eba.c > +++ b/drivers/mtd/ubi/eba.c > @@ -481,6 +481,62 @@ out_unlock: > } > > /** > + * ubi_eba_read_leb_sg - read data into a scatter gather list. > + * @ubi: UBI device description object > + * @vol: volume description object > + * @lnum: logical eraseblock number > + * @sgl: UBI scatter gather list to store the read data > + * @offset: offset from where to read > + * @len: how many bytes to read > + * @check: data CRC check flag > + * > + * This function works exactly like ubi_eba_read_leb(). But instead of > + * storing the read data into a buffer it writes to an UBI scatter gather > + * list. > + */ > +int ubi_eba_read_leb_sg(struct ubi_device *ubi, struct ubi_volume *vol, > + struct ubi_sgl *sgl, int lnum, int offset, int len, > + int check) > +{ > + int to_read; > + int ret; > + struct scatterlist *sg; > + > + for (;;) { > + ubi_assert(sgl->list_pos < UBI_MAX_SG_COUNT); > + sg = &sgl->sg[sgl->list_pos]; > + if (len < sg->length - sgl->page_pos) > + to_read = len; > + else > + to_read = sg->length - sgl->page_pos; > + > + ret = ubi_eba_read_leb(ubi, vol, lnum, > + sg_virt(sg) + sgl->page_pos, offset, > + to_read, check); > + if (ret < 0) > + goto out;
Matter of taste, but isn't it better to just return here?
> + > + offset += to_read; > + len -= to_read; > + if (!len) { > + sgl->page_pos += to_read; > + if (sgl->page_pos == sg->length) { > + sgl->list_pos++; > + sgl->page_pos = 0; > + } > + > + break; > + } > + > + sgl->list_pos++; > + sgl->page_pos = 0; > + } > + > +out: > + return ret; > +} > + > +/** > * recover_peb - recover from write failure. > * @ubi: UBI device description object > * @pnum: the physical eraseblock to recover > diff --git a/drivers/mtd/ubi/kapi.c b/drivers/mtd/ubi/kapi.c > index f3bab66..d0055a2 100644 > --- a/drivers/mtd/ubi/kapi.c > +++ b/drivers/mtd/ubi/kapi.c > @@ -355,6 +355,43 @@ void ubi_close_volume(struct ubi_volume_desc *desc) > EXPORT_SYMBOL_GPL(ubi_close_volume); > > /** > + * leb_read_sanity_check - does sanity checks on read requests. > + * @desc: volume descriptor > + * @lnum: logical eraseblock number to read from > + * @offset: offset within the logical eraseblock to read from > + * @len: how many bytes to read > + * > + * This function is used by ubi_leb_read() and ubi_leb_read_sg() > + * to perfrom sanity checks.
s/perfrom/perform
> + */ > +static int leb_read_sanity_check(struct ubi_volume_desc *desc, int lnum, > + int offset, int len) > +{ > + struct ubi_volume *vol = desc->vol; > + struct ubi_device *ubi = vol->ubi; > + int vol_id = vol->vol_id; > + > + if (vol_id < 0 || vol_id >= ubi->vtbl_slots || lnum < 0 || > + lnum >= vol->used_ebs || offset < 0 || len < 0 || > + offset + len > vol->usable_leb_size) > + return -EINVAL; > + > + if (vol->vol_type == UBI_STATIC_VOLUME) { > + if (vol->used_ebs == 0) > + /* Empty static UBI volume */ > + return 0; > + if (lnum == vol->used_ebs - 1 && > + offset + len > vol->last_eb_bytes) > + return -EINVAL; > + } > + > + if (vol->upd_marker) > + return -EBADF; > + > + return 0; > +} > + > +/** > * ubi_leb_read - read data. > * @desc: volume descriptor > * @lnum: logical eraseblock number to read from > @@ -390,22 +427,10 @@ int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset, > > dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset); > > - if (vol_id < 0 || vol_id >= ubi->vtbl_slots || lnum < 0 || > - lnum >= vol->used_ebs || offset < 0 || len < 0 || > - offset + len > vol->usable_leb_size) > - return -EINVAL; > - > - if (vol->vol_type == UBI_STATIC_VOLUME) { > - if (vol->used_ebs == 0) > - /* Empty static UBI volume */ > - return 0; > - if (lnum == vol->used_ebs - 1 && > - offset + len > vol->last_eb_bytes) > - return -EINVAL; > - } > + err = leb_read_sanity_check(desc, lnum, offset, len); > + if (err < 0) > + return err; > > - if (vol->upd_marker) > - return -EBADF; > if (len == 0) > return 0; > > @@ -419,6 +444,46 @@ int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset, > } > EXPORT_SYMBOL_GPL(ubi_leb_read); > > + > +/** > + * ubi_leb_read_sg - read data into a scatter gather list. > + * @desc: volume descriptor > + * @lnum: logical eraseblock number to read from > + * @buf: buffer where to store the read data > + * @offset: offset within the logical eraseblock to read from > + * @len: how many bytes to read > + * @check: whether UBI has to check the read data's CRC or not. > + * > + * This function works exactly like ubi_leb_read_sg(). But instead of > + * storing the read data into a buffer it writes to an UBI scatter gather > + * list. > + */ > +int ubi_leb_read_sg(struct ubi_volume_desc *desc, int lnum, struct ubi_sgl *sgl, > + int offset, int len, int check) > +{ > + struct ubi_volume *vol = desc->vol; > + struct ubi_device *ubi = vol->ubi; > + int err, vol_id = vol->vol_id; > + > + dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset); > + > + err = leb_read_sanity_check(desc, lnum, offset, len); > + if (err < 0) > + return err; > + > + if (len == 0) > + return 0; > + > + err = ubi_eba_read_leb_sg(ubi, vol, sgl, lnum, offset, len, check); > + if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) { > + ubi_warn(ubi, "mark volume %d as corrupted", vol_id); > + vol->corrupted = 1; > + } > + > + return err; > +} > +EXPORT_SYMBOL_GPL(ubi_leb_read_sg); > + > /** > * ubi_leb_write - write data. > * @desc: volume descriptor > diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h > index ee7ac0b..a5283cf 100644 > --- a/drivers/mtd/ubi/ubi.h > +++ b/drivers/mtd/ubi/ubi.h > @@ -791,6 +791,9 @@ int ubi_eba_unmap_leb(struct ubi_device *ubi, struct ubi_volume *vol, > int lnum); > int ubi_eba_read_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum, > void *buf, int offset, int len, int check); > +int ubi_eba_read_leb_sg(struct ubi_device *ubi, struct ubi_volume *vol, > + struct ubi_sgl *sgl, int lnum, int offset, int len, > + int check); > int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum, > const void *buf, int offset, int len); > int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol, > diff --git a/include/linux/mtd/ubi.h b/include/linux/mtd/ubi.h > index c3918a0..3d5916d 100644 > --- a/include/linux/mtd/ubi.h > +++ b/include/linux/mtd/ubi.h > @@ -23,11 +23,16 @@ > > #include <linux/ioctl.h> > #include <linux/types.h> > +#include <linux/scatterlist.h> > #include <mtd/ubi-user.h> > > /* All voumes/LEBs */ > #define UBI_ALL -1 > > +/* Maximum number of scatter gather list entries, > + * we use only 64 to have a lower memory foot print. */
Multilines comments style is:
/* * */
> +#define UBI_MAX_SG_COUNT 64 > + > /* > * enum ubi_open_mode - UBI volume open mode constants. > * > @@ -116,6 +121,35 @@ struct ubi_volume_info { > }; > > /** > + * struct ubi_sgl - UBI scatter gather list data structure. > + * @list_pos: current position in @sg[] > + * @page_pos: current position in @sg[@list_pos] > + * @sg: the scatter gather list itself > + * > + * ubi_sgl is a wrapper around a scatter list which keeps track of the > + * current position in the list and the current list item such that > + * it can be used across multiple ubi_leb_read_sg() calls. > + */ > +struct ubi_sgl { > + int list_pos; > + int page_pos; > + struct scatterlist sg[UBI_MAX_SG_COUNT]; > +}; > + > +/** > + * ubi_sgl_init - initialize an UBI scatter gather list data structure. > + * @usgl: the UBI scatter gather struct itself > + * > + * Please note that you still have to use sg_init_table() or any adequate > + * function to initialize the unterlaying struct scatterlist. > + */ > +static inline void ubi_sgl_init(struct ubi_sgl *usgl) > +{ > + usgl->list_pos = 0; > + usgl->page_pos = 0; > +} > + > +/** > * struct ubi_device_info - UBI device description data structure. > * @ubi_num: ubi device number > * @leb_size: logical eraseblock size on this UBI device > @@ -210,6 +244,8 @@ int ubi_unregister_volume_notifier(struct notifier_block *nb); > void ubi_close_volume(struct ubi_volume_desc *desc); > int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset, > int len, int check); > +int ubi_leb_read_sg(struct ubi_volume_desc *desc, int lnum, struct ubi_sgl *sgl, > + int offset, int len, int check); > int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf, > int offset, int len); > int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf, > @@ -230,4 +266,14 @@ static inline int ubi_read(struct ubi_volume_desc *desc, int lnum, char *buf, > { > return ubi_leb_read(desc, lnum, buf, offset, len, 0); > } > + > +/* > + * This function is the same as the 'ubi_leb_read_sg()' function, but it does > + * not provide the checking capability. > + */ > +static inline int ubi_read_sg(struct ubi_volume_desc *desc, int lnum, > + struct ubi_sgl *sgl, int offset, int len) > +{ > + return ubi_leb_read_sg(desc, lnum, sgl, offset, len, 0); > +} > #endif /* !__LINUX_UBI_H__ */ >
-- Ezequiel Garcia, VanguardiaSur www.vanguardiasur.com.ar
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