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Message-ID: <202003181144.BD1DE93@keescook>
Date: Wed, 18 Mar 2020 11:47:20 -0700
From: Kees Cook <keescook@...omium.org>
To: WeiXiong Liao <liaoweixiong@...winnertech.com>
Cc: Anton Vorontsov <anton@...msg.org>,
Colin Cross <ccross@...roid.com>,
Tony Luck <tony.luck@...el.com>,
Jonathan Corbet <corbet@....net>,
Miquel Raynal <miquel.raynal@...tlin.com>,
Richard Weinberger <richard@....at>,
Vignesh Raghavendra <vigneshr@...com>,
Mauro Carvalho Chehab <mchehab+samsung@...nel.org>,
"David S. Miller" <davem@...emloft.net>,
Rob Herring <robh@...nel.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Jonathan Cameron <Jonathan.Cameron@...wei.com>,
linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-mtd@...ts.infradead.org
Subject: Re: [PATCH v2 09/11] pstore/blk: blkoops: support special removing
jobs for dmesg.
On Fri, Feb 07, 2020 at 08:25:53PM +0800, WeiXiong Liao wrote:
> It's one of a series of patches for adaptive to MTD device.
>
> MTD device is not block device. To write to flash device on MTD, erase
> must to be done before. However, pstore/blk just set datalen as 0 when
> remove, which is not enough for mtd device. That's why this patch here,
> to support special jobs when removing pstore/blk record.
>
> Signed-off-by: WeiXiong Liao <liaoweixiong@...winnertech.com>
> ---
> Documentation/admin-guide/pstore-block.rst | 9 +++++++++
> fs/pstore/blkoops.c | 4 +++-
> fs/pstore/blkzone.c | 9 ++++++++-
> include/linux/blkoops.h | 10 ++++++++++
> include/linux/pstore_blk.h | 11 +++++++++++
> 5 files changed, 41 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/admin-guide/pstore-block.rst b/Documentation/admin-guide/pstore-block.rst
> index 299142b3d8e6..1735476621df 100644
> --- a/Documentation/admin-guide/pstore-block.rst
> +++ b/Documentation/admin-guide/pstore-block.rst
> @@ -200,6 +200,15 @@ negative number will be returned. The following return numbers mean more:
> 1. -EBUSY: pstore/blk should try again later.
> #. -ENEXT: this zone is used or broken, pstore/blk should try next one.
>
> +erase
> +~~~~~
> +
> +It's generic erase API for pstore/blk, which is requested by non-block device.
> +It will be called while pstore record is removing. It's required only when the
> +device has special removing jobs. For example, MTD device tries to erase block.
> +
> +Normally zero should be returned, otherwise it indicates an error.
> +
> panic_write (for non-block device)
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> diff --git a/fs/pstore/blkoops.c b/fs/pstore/blkoops.c
> index 01170b344f00..7cf4731e52f7 100644
> --- a/fs/pstore/blkoops.c
> +++ b/fs/pstore/blkoops.c
> @@ -164,6 +164,7 @@ int blkoops_register_device(struct blkoops_device *bo_dev)
> bzinfo->dump_oops = dump_oops;
> bzinfo->read = bo_dev->read;
> bzinfo->write = bo_dev->write;
> + bzinfo->erase = bo_dev->erase;
> bzinfo->panic_write = bo_dev->panic_write;
> bzinfo->name = "blkoops";
> bzinfo->owner = THIS_MODULE;
> @@ -383,10 +384,11 @@ int blkoops_register_blkdev(unsigned int major, unsigned int flags,
> bo_dev.total_size = blkoops_bdev_size(bdev);
> if (bo_dev.total_size == 0)
> goto err_put_bdev;
> - bo_dev.panic_write = panic_write ? blkoops_blk_panic_write : NULL;
> bo_dev.flags = flags;
> bo_dev.read = blkoops_generic_blk_read;
> bo_dev.write = blkoops_generic_blk_write;
> + bo_dev.erase = NULL;
> + bo_dev.panic_write = panic_write ? blkoops_blk_panic_write : NULL;
>
> ret = blkoops_register_device(&bo_dev);
> if (ret)
I think this patch, like the prior, needs to be reordered in the series.
How about adding
blkoops_register_device()
as a single patch, which is what provides support for the "non-block"
block devices? Then the blkoops_register_blkdev() can stand alone in the
first patch?
It just might be easier to review, since nothing uses
blkoops_register_device() until the mtd driver is added. So that
function and this patch would go together as a single "support non-block
devices" change.
> diff --git a/fs/pstore/blkzone.c b/fs/pstore/blkzone.c
> index 205aeff28992..a17fff77b875 100644
> --- a/fs/pstore/blkzone.c
> +++ b/fs/pstore/blkzone.c
> @@ -593,11 +593,18 @@ static inline bool blkz_ok(struct blkz_zone *zone)
> static inline int blkz_dmesg_erase(struct blkz_context *cxt,
> struct blkz_zone *zone)
> {
> + size_t size;
> +
> if (unlikely(!blkz_ok(zone)))
> return 0;
>
> atomic_set(&zone->buffer->datalen, 0);
> - return blkz_zone_write(zone, FLUSH_META, NULL, 0, 0);
> +
> + size = buffer_datalen(zone) + sizeof(*zone->buffer);
> + if (cxt->bzinfo->erase)
> + return cxt->bzinfo->erase(size, zone->off);
> + else
> + return blkz_zone_write(zone, FLUSH_META, NULL, 0, 0);
> }
>
> static inline int blkz_record_erase(struct blkz_context *cxt,
> diff --git a/include/linux/blkoops.h b/include/linux/blkoops.h
> index bc7665d14a98..11cb3036ad5f 100644
> --- a/include/linux/blkoops.h
> +++ b/include/linux/blkoops.h
> @@ -33,6 +33,15 @@
> * number means more:
> * -EBUSY: pstore/blk should try again later.
> * -ENEXT: this zone is used or broken, pstore/blk should try next one.
> + * @erase:
> + * The general (not panic) erase operation. It will be call while pstore
> + * record is removing. It's required only when device have special
> + * removing jobs, for example, MTD device try to erase block.
> + *
> + * Both of the @size and @offset parameters on this interface are
> + * the relative size of the space provided, not the whole disk/flash.
> + *
> + * On success, 0 should be returned. Others mean error.
> * @panic_write:
> * The write operation only used for panic.
> *
> @@ -53,6 +62,7 @@ struct blkoops_device {
> unsigned long total_size;
> blkz_read_op read;
> blkz_write_op write;
> + blkz_erase_op erase;
> blkz_write_op panic_write;
> };
>
> diff --git a/include/linux/pstore_blk.h b/include/linux/pstore_blk.h
> index bbbe4fe37f7c..9641969f888f 100644
> --- a/include/linux/pstore_blk.h
> +++ b/include/linux/pstore_blk.h
> @@ -46,6 +46,15 @@
> * number means more:
> * -EBUSY: pstore/blk should try again later.
> * -ENEXT: this zone is used or broken, pstore/blk should try next one.
> + * @erase:
> + * The general (not panic) erase operation. It will be call while pstore
> + * record is removing. It's required only when device have special
> + * removing jobs, for example, MTD device try to erase block.
> + *
> + * Both of the @size and @offset parameters on this interface are
> + * the relative size of the space provided, not the whole disk/flash.
> + *
> + * On success, 0 should be returned. Others mean error.
> * @panic_write:
> * The write operation only used for panic. It's optional if you do not
> * care panic record. If panic occur but blkzone do not recover yet, the
> @@ -59,6 +68,7 @@
> */
> typedef ssize_t (*blkz_read_op)(char *, size_t, loff_t);
> typedef ssize_t (*blkz_write_op)(const char *, size_t, loff_t);
> +typedef ssize_t (*blkz_erase_op)(size_t, loff_t);
> struct blkz_info {
> struct module *owner;
> const char *name;
> @@ -71,6 +81,7 @@ struct blkz_info {
> int dump_oops;
> blkz_read_op read;
> blkz_write_op write;
> + blkz_erase_op erase;
> blkz_write_op panic_write;
> };
>
> --
> 1.9.1
>
--
Kees Cook
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