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Date:   Tue, 19 Jan 2021 04:11:31 +0000
From:   Bhaskara Budiredla <bbudiredla@...vell.com>
To:     Ulf Hansson <ulf.hansson@...aro.org>
CC:     Kees Cook <keescook@...omium.org>,
        Colin Cross <ccross@...roid.com>,
        "Tony Luck" <tony.luck@...el.com>,
        Sunil Kovvuri Goutham <sgoutham@...vell.com>,
        "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
        "Linux Kernel Mailing List" <linux-kernel@...r.kernel.org>
Subject: RE: [EXT] Re: [PATCH v4 1/2] mmc: Support kmsg dumper based on
 pstore/blk

Hi Kees,

Do you see any issues to ACK this if the mmc pstore
registration is through register_pstore_blk()?
As Uffe said, eMMC would need to go through
psblk_generic_blk_read()/write() instead of
mmcpstore_read()/write().

Thanks,
Bhaskara

>-----Original Message-----
>From: Ulf Hansson <ulf.hansson@...aro.org>
>Sent: Wednesday, January 13, 2021 5:16 PM
>To: Bhaskara Budiredla <bbudiredla@...vell.com>
>Cc: Kees Cook <keescook@...omium.org>; Colin Cross
><ccross@...roid.com>; Tony Luck <tony.luck@...el.com>; Sunil Kovvuri
>Goutham <sgoutham@...vell.com>; linux-mmc@...r.kernel.org; Linux
>Kernel Mailing List <linux-kernel@...r.kernel.org>
>Subject: [EXT] Re: [PATCH v4 1/2] mmc: Support kmsg dumper based on
>pstore/blk
>
>External Email
>
>----------------------------------------------------------------------
>On Wed, 23 Dec 2020 at 15:41, Bhaskara Budiredla
><bbudiredla@...vell.com> wrote:
>>
>> This patch introduces to mmcpstore. The functioning of mmcpstore is
>> similar to mtdpstore. mmcpstore works on FTL based flash devices
>> whereas mtdpstore works on raw flash devices. When the system crashes,
>> mmcpstore stores the kmsg panic and oops logs to a user specified MMC
>> device.
>>
>> It collects the details about the host MMC device through pstore/blk
>> "blkdev" parameter. The user can specify the MMC device in many ways
>> by checking in Documentation/admin-guide/pstore-blk.rst.
>>
>> The individual mmc host drivers have to define suitable polling and
>> cleanup subroutines to write kmsg panic/oops logs through mmcpstore.
>> These new host operations are needed as pstore panic write runs with
>> interrupts disabled.
>>
>> Signed-off-by: Bhaskara Budiredla <bbudiredla@...vell.com>
>
>Just to make it clear, to avoid confusions.
>
>I will not consider to pick this up, as long as the *non-panic* read/write
>support is implemented through pstore specific callbacks.
>Instead those requests should go through the regular block I/O path, as like
>any other file system.
>
>Kind regards
>Ulf Hansson
>
>> ---
>>  drivers/mmc/core/Kconfig     |  14 +-
>>  drivers/mmc/core/Makefile    |   1 +
>>  drivers/mmc/core/block.c     |  19 +++
>>  drivers/mmc/core/block.h     |   9 +
>>  drivers/mmc/core/core.c      |  44 +++++
>>  drivers/mmc/core/mmcpstore.c | 310
>+++++++++++++++++++++++++++++++++++
>>  include/linux/mmc/core.h     |   5 +
>>  include/linux/mmc/host.h     |  12 ++
>>  8 files changed, 413 insertions(+), 1 deletion(-)  create mode 100644
>> drivers/mmc/core/mmcpstore.c
>>
>> diff --git a/drivers/mmc/core/Kconfig b/drivers/mmc/core/Kconfig index
>> c12fe13e4b14..4c651da4f2d2 100644
>> --- a/drivers/mmc/core/Kconfig
>> +++ b/drivers/mmc/core/Kconfig
>> @@ -34,9 +34,22 @@ config PWRSEQ_SIMPLE
>>           This driver can also be built as a module. If so, the module
>>           will be called pwrseq_simple.
>>
>> +config MMC_PSTORE_BACKEND
>> +       bool "Log panic/oops to a MMC buffer"
>> +       depends on MMC_BLOCK
>> +       help
>> +         This option will let you create platform backend to store kmsg
>> +         crash dumps to a user specified MMC device. This is primarily
>> +         based on pstore/blk.
>> +
>> +config MMC_PSTORE
>> +       tristate
>> +       select PSTORE_BLK
>> +
>>  config MMC_BLOCK
>>         tristate "MMC block device driver"
>>         depends on BLOCK
>> +       select MMC_PSTORE if MMC_PSTORE_BACKEND=y
>>         default y
>>         help
>>           Say Y here to enable the MMC block device driver support.
>> @@ -80,4 +93,3 @@ config MMC_TEST
>>
>>           This driver is only of interest to those developing or
>>           testing a host driver. Most people should say N here.
>> -
>> diff --git a/drivers/mmc/core/Makefile b/drivers/mmc/core/Makefile
>> index 95ffe008ebdf..7cb9a3af4827 100644
>> --- a/drivers/mmc/core/Makefile
>> +++ b/drivers/mmc/core/Makefile
>> @@ -16,5 +16,6 @@ obj-$(CONFIG_PWRSEQ_EMMC)     += pwrseq_emmc.o
>>  mmc_core-$(CONFIG_DEBUG_FS)    += debugfs.o
>>  obj-$(CONFIG_MMC_BLOCK)                += mmc_block.o
>>  mmc_block-objs                 := block.o queue.o
>> +mmc_block-$(CONFIG_MMC_PSTORE) += mmcpstore.o
>>  obj-$(CONFIG_MMC_TEST)         += mmc_test.o
>>  obj-$(CONFIG_SDIO_UART)                += sdio_uart.o
>> diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c index
>> 8d3df0be0355..ed012a91e3a3 100644
>> --- a/drivers/mmc/core/block.c
>> +++ b/drivers/mmc/core/block.c
>> @@ -2870,6 +2870,21 @@ static void mmc_blk_remove_debugfs(struct
>> mmc_card *card,
>>
>>  #endif /* CONFIG_DEBUG_FS */
>>
>> +#if IS_ENABLED(CONFIG_MMC_PSTORE)
>> +sector_t mmc_blk_get_part(struct mmc_card *card, int part_num,
>> +sector_t *size) {
>> +       struct mmc_blk_data *md = dev_get_drvdata(&card->dev);
>> +       struct gendisk *disk = md->disk;
>> +       struct disk_part_tbl *part_tbl = disk->part_tbl;
>> +
>> +       if (part_num < 0 || part_num >= part_tbl->len)
>> +               return 0;
>> +
>> +       *size = part_tbl->part[part_num]->nr_sects << SECTOR_SHIFT;
>> +       return part_tbl->part[part_num]->start_sect;
>> +}
>> +#endif
>> +
>>  static int mmc_blk_probe(struct mmc_card *card)  {
>>         struct mmc_blk_data *md, *part_md; @@ -2913,6 +2928,9 @@
>> static int mmc_blk_probe(struct mmc_card *card)
>>                         goto out;
>>         }
>>
>> +       if (mmc_card_mmc(card) || mmc_card_sd(card))
>> +               mmcpstore_card_set(card, md->disk->disk_name);
>> +
>>         /* Add two debugfs entries */
>>         mmc_blk_add_debugfs(card, md);
>>
>> @@ -3060,6 +3078,7 @@ static void __exit mmc_blk_exit(void)
>>         unregister_blkdev(MMC_BLOCK_MAJOR, "mmc");
>>         unregister_chrdev_region(mmc_rpmb_devt, MAX_DEVICES);
>>         bus_unregister(&mmc_rpmb_bus_type);
>> +       unregister_mmcpstore();
>>  }
>>
>>  module_init(mmc_blk_init);
>> diff --git a/drivers/mmc/core/block.h b/drivers/mmc/core/block.h index
>> 31153f656f41..2a4ee5568194 100644
>> --- a/drivers/mmc/core/block.h
>> +++ b/drivers/mmc/core/block.h
>> @@ -16,5 +16,14 @@ void mmc_blk_mq_recovery(struct mmc_queue
>*mq);
>> struct work_struct;
>>
>>  void mmc_blk_mq_complete_work(struct work_struct *work);
>> +#if IS_ENABLED(CONFIG_MMC_PSTORE)
>> +sector_t mmc_blk_get_part(struct mmc_card *card, int part_num,
>> +sector_t *size); void mmcpstore_card_set(struct mmc_card *card, const
>> +char *disk_name); void unregister_mmcpstore(void); #else static
>> +inline void mmcpstore_card_set(struct mmc_card *card,
>> +                                       const char *disk_name) {}
>> +static inline void unregister_mmcpstore(void) {} #endif
>>
>>  #endif
>> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index
>> d42037f0f10d..32df03f4c848 100644
>> --- a/drivers/mmc/core/core.c
>> +++ b/drivers/mmc/core/core.c
>> @@ -569,6 +569,30 @@ int mmc_cqe_recovery(struct mmc_host *host)  }
>> EXPORT_SYMBOL(mmc_cqe_recovery);
>>
>> +#if IS_ENABLED(CONFIG_MMC_PSTORE)
>> +/**
>> + *     mmc_wait_for_pstore_req - initiate a blocking mmc request
>> + *     @host: MMC host to start command
>> + *     @mrq: MMC request to start
>> + *
>> + *     Start a blocking MMC request for a host and wait for the request
>> + *     to complete that is based on polling and timeout.
>> + */
>> +void mmc_wait_for_pstore_req(struct mmc_host *host, struct
>> +mmc_request *mrq) {
>> +       unsigned int timeout;
>> +
>> +       host->ops->req_cleanup_pending(host);
>> +       mmc_start_request(host, mrq);
>> +
>> +       if (mrq->data) {
>> +               timeout = mrq->data->timeout_ns / NSEC_PER_MSEC;
>> +               host->ops->req_completion_poll(host, timeout);
>> +       }
>> +}
>> +EXPORT_SYMBOL(mmc_wait_for_pstore_req);
>> +#endif
>> +
>>  /**
>>   *     mmc_is_req_done - Determine if a 'cap_cmd_during_tfr' request is
>done
>>   *     @host: MMC host
>> @@ -817,6 +841,26 @@ int __mmc_claim_host(struct mmc_host *host,
>> struct mmc_ctx *ctx,  }  EXPORT_SYMBOL(__mmc_claim_host);
>>
>> +#if IS_ENABLED(CONFIG_MMC_PSTORE)
>> +/**
>> + *     mmc_claim_host_async - claim host in atomic context
>> + *     @host: mmc host to claim
>> + *
>> + *     This routine may be called in panic/oops scenarios.
>> + *     Return zero with host claim success, else busy status.
>> + */
>> +int mmc_claim_host_async(struct mmc_host *host) {
>> +       if (!host->claimed && pm_runtime_active(mmc_dev(host))) {
>> +               host->claimed = 1;
>> +               return 0;
>> +       }
>> +
>> +       return -EBUSY;
>> +}
>> +EXPORT_SYMBOL(mmc_claim_host_async);
>> +#endif
>> +
>>  /**
>>   *     mmc_release_host - release a host
>>   *     @host: mmc host to release
>> diff --git a/drivers/mmc/core/mmcpstore.c
>> b/drivers/mmc/core/mmcpstore.c new file mode 100644 index
>> 000000000000..d7abe82612cb
>> --- /dev/null
>> +++ b/drivers/mmc/core/mmcpstore.c
>> @@ -0,0 +1,310 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * MMC pstore support based on pstore/blk
>> + *
>> + * Copyright (c) 2020 Marvell.
>> + * Author: Bhaskara Budiredla <bbudiredla@...vell.com>  */
>> +
>> +#define pr_fmt(fmt) "mmcpstore: " fmt
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/pstore_blk.h>
>> +#include <linux/blkdev.h>
>> +#include <linux/mount.h>
>> +#include <linux/slab.h>
>> +#include <linux/mmc/mmc.h>
>> +#include <linux/mmc/host.h>
>> +#include <linux/mmc/card.h>
>> +#include <linux/scatterlist.h>
>> +#include "block.h"
>> +#include "card.h"
>> +#include "core.h"
>> +
>> +static struct mmcpstore_context {
>> +       char dev_name[BDEVNAME_SIZE];
>> +       int partno;
>> +       sector_t start_sect;
>> +       sector_t size;
>> +       struct pstore_device_info dev;
>> +       struct pstore_blk_config conf;
>> +       struct pstore_blk_info info;
>> +
>> +       char *sub;
>> +       struct mmc_card *card;
>> +       struct mmc_request *mrq;
>> +} oops_cxt;
>> +
>> +static void mmc_prep_req(struct mmc_request *mrq,
>> +               unsigned int sect_offset, unsigned int nsects,
>> +               struct scatterlist *sg, u32 opcode, unsigned int
>> +flags) {
>> +       mrq->cmd->opcode = opcode;
>> +       mrq->cmd->arg = sect_offset;
>> +       mrq->cmd->flags = MMC_RSP_R1 | MMC_CMD_ADTC;
>> +
>> +       if (nsects == 1) {
>> +               mrq->stop = NULL;
>> +       } else {
>> +               mrq->stop->opcode = MMC_STOP_TRANSMISSION;
>> +               mrq->stop->arg = 0;
>> +               mrq->stop->flags = MMC_RSP_R1B | MMC_CMD_AC;
>> +       }
>> +
>> +       mrq->data->blksz = SECTOR_SIZE;
>> +       mrq->data->blocks = nsects;
>> +       mrq->data->flags = flags;
>> +       mrq->data->sg = sg;
>> +       mrq->data->sg_len = 1;
>> +}
>> +
>> +static int mmcpstore_rdwr_req(const char *buf, unsigned int nsects,
>> +                       unsigned int sect_offset, unsigned int flags)
>> +{
>> +       struct mmcpstore_context *cxt = &oops_cxt;
>> +       struct mmc_request *mrq = cxt->mrq;
>> +       struct mmc_card *card = cxt->card;
>> +       struct mmc_host *host = card->host;
>> +       struct scatterlist sg;
>> +       u32 opcode;
>> +
>> +       if (flags == MMC_DATA_READ)
>> +               opcode  = (nsects > 1) ?
>> +                       MMC_READ_MULTIPLE_BLOCK : MMC_READ_SINGLE_BLOCK;
>> +       else
>> +               opcode = (nsects > 1) ?
>> +                       MMC_WRITE_MULTIPLE_BLOCK : MMC_WRITE_BLOCK;
>> +
>> +       mmc_prep_req(mrq, sect_offset, nsects, &sg, opcode, flags);
>> +       sg_init_one(&sg, buf, (nsects << SECTOR_SHIFT));
>> +       mmc_set_data_timeout(mrq->data, cxt->card);
>> +
>> +       mmc_claim_host(host);
>> +       mmc_wait_for_req(host, mrq);
>> +       mdelay(mrq->data->timeout_ns / NSEC_PER_MSEC);
>> +       mmc_release_host(host);
>> +
>> +       if (mrq->cmd->error) {
>> +               pr_err("Cmd error: %d\n", mrq->cmd->error);
>> +               return mrq->cmd->error;
>> +       }
>> +       if (mrq->data->error) {
>> +               pr_err("Data error: %d\n", mrq->data->error);
>> +               return mrq->data->error;
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>> +static ssize_t mmcpstore_write(const char *buf, size_t size, loff_t
>> +off) {
>> +       struct mmcpstore_context *cxt = &oops_cxt;
>> +       int ret;
>> +
>> +       ret = mmcpstore_rdwr_req(buf, (size >> SECTOR_SHIFT),
>> +               cxt->start_sect + (off >> SECTOR_SHIFT), MMC_DATA_WRITE);
>> +       if (ret)
>> +               return ret;
>> +
>> +       return size;
>> +}
>> +
>> +static ssize_t mmcpstore_read(char *buf, size_t size, loff_t off) {
>> +       struct mmcpstore_context *cxt = &oops_cxt;
>> +       unsigned int sect_off = cxt->start_sect  + (off >> SECTOR_SHIFT);
>> +       unsigned long sects = (cxt->conf.kmsg_size >> SECTOR_SHIFT);
>> +       int ret;
>> +
>> +       if (unlikely(!buf || !size))
>> +               return -EINVAL;
>> +
>> +       ret = mmcpstore_rdwr_req(cxt->sub, sects, sect_off,
>MMC_DATA_READ);
>> +       if (ret)
>> +               return ret;
>> +       memcpy(buf, cxt->sub, size);
>> +
>> +       return size;
>> +}
>> +
>> +static int mmcpstore_panic_write_req(const char *buf,
>> +               unsigned int nsects, unsigned int sect_offset) {
>> +       struct mmcpstore_context *cxt = &oops_cxt;
>> +       struct mmc_request *mrq = cxt->mrq;
>> +       struct mmc_card *card = cxt->card;
>> +       struct mmc_host *host = card->host;
>> +       struct scatterlist sg;
>> +       u32 opcode;
>> +       int ret;
>> +
>> +       opcode = (nsects > 1) ? MMC_WRITE_MULTIPLE_BLOCK :
>MMC_WRITE_BLOCK;
>> +       mmc_prep_req(mrq, sect_offset, nsects, &sg, opcode,
>MMC_DATA_WRITE);
>> +       sg_init_one(&sg, buf, (nsects << SECTOR_SHIFT));
>> +       mmc_set_data_timeout(mrq->data, cxt->card);
>> +
>> +       ret = mmc_claim_host_async(host);
>> +       if (ret)
>> +               return ret;
>> +
>> +       mmc_wait_for_pstore_req(host, mrq);
>> +       return 0;
>> +}
>> +
>> +static ssize_t mmcpstore_panic_write(const char *buf, size_t size,
>> +loff_t off) {
>> +       struct mmcpstore_context *cxt = &oops_cxt;
>> +       int ret;
>> +
>> +       ret = mmcpstore_panic_write_req(buf, (size >> SECTOR_SHIFT),
>> +                       cxt->start_sect + (off >> SECTOR_SHIFT));
>> +       if (ret)
>> +               return ret;
>> +
>> +       return size;
>> +}
>> +
>> +static struct block_device *mmcpstore_open_backend(const char
>> +*device) {
>> +       struct block_device *bdev;
>> +       dev_t devt;
>> +
>> +       bdev = blkdev_get_by_path(device, FMODE_READ, NULL);
>> +       if (IS_ERR(bdev)) {
>> +               devt = name_to_dev_t(device);
>> +               if (devt == 0)
>> +                       return ERR_PTR(-ENODEV);
>> +
>> +               bdev = blkdev_get_by_dev(devt, FMODE_READ, NULL);
>> +               if (IS_ERR(bdev))
>> +                       return bdev;
>> +       }
>> +
>> +       return bdev;
>> +}
>> +
>> +static void mmcpstore_close_backend(struct block_device *bdev) {
>> +       if (!bdev)
>> +               return;
>> +       blkdev_put(bdev, FMODE_READ);
>> +}
>> +
>> +void mmcpstore_card_set(struct mmc_card *card, const char *disk_name)
>> +{
>> +       struct mmcpstore_context *cxt = &oops_cxt;
>> +       struct pstore_blk_config *conf = &cxt->conf;
>> +       struct pstore_device_info *dev = &cxt->dev;
>> +       struct block_device *bdev;
>> +       struct mmc_command *stop;
>> +       struct mmc_command *cmd;
>> +       struct mmc_request *mrq;
>> +       struct mmc_data *data;
>> +       int ret;
>> +
>> +       ret = pstore_blk_get_config(conf);
>> +       if (!conf->device[0]) {
>> +               pr_debug("psblk backend is empty\n");
>> +               return;
>> +       }
>> +
>> +       /* Multiple backend devices not allowed */
>> +       if (cxt->dev_name[0])
>> +               return;
>> +
>> +       bdev =  mmcpstore_open_backend(conf->device);
>> +       if (IS_ERR(bdev)) {
>> +               pr_err("%s failed to open with %ld\n",
>> +                               conf->device, PTR_ERR(bdev));
>> +               return;
>> +       }
>> +
>> +       bdevname(bdev, cxt->dev_name);
>> +       cxt->partno = bdev->bd_part->partno;
>> +       mmcpstore_close_backend(bdev);
>> +
>> +       if (strncmp(cxt->dev_name, disk_name, strlen(disk_name)))
>> +               return;
>> +
>> +       cxt->start_sect = mmc_blk_get_part(card, cxt->partno, &cxt->size);
>> +       if (!cxt->start_sect) {
>> +               pr_err("Non-existent partition %d selected\n", cxt->partno);
>> +               return;
>> +       }
>> +
>> +       /* Check for host mmc panic write polling function definitions */
>> +       if (!card->host->ops->req_cleanup_pending ||
>> +                       !card->host->ops->req_completion_poll)
>> +               return;
>> +
>> +       cxt->card = card;
>> +
>> +       cxt->sub = kmalloc(conf->kmsg_size, GFP_KERNEL);
>> +       if (!cxt->sub)
>> +               goto out;
>> +
>> +       mrq = kzalloc(sizeof(struct mmc_request), GFP_KERNEL);
>> +       if (!mrq)
>> +               goto free_sub;
>> +
>> +       cmd = kzalloc(sizeof(struct mmc_command), GFP_KERNEL);
>> +       if (!cmd)
>> +               goto free_mrq;
>> +
>> +       stop = kzalloc(sizeof(struct mmc_command), GFP_KERNEL);
>> +       if (!stop)
>> +               goto free_cmd;
>> +
>> +       data = kzalloc(sizeof(struct mmc_data), GFP_KERNEL);
>> +       if (!data)
>> +               goto free_stop;
>> +
>> +       mrq->cmd = cmd;
>> +       mrq->data = data;
>> +       mrq->stop = stop;
>> +       cxt->mrq = mrq;
>> +
>> +       dev->total_size = cxt->size;
>> +       dev->flags = PSTORE_FLAGS_DMESG;
>> +       dev->read = mmcpstore_read;
>> +       dev->write = mmcpstore_write;
>> +       dev->erase = NULL;
>> +       dev->panic_write = mmcpstore_panic_write;
>> +
>> +       ret = register_pstore_device(&cxt->dev);
>> +       if (ret) {
>> +               pr_err("%s registering with psblk failed (%d)\n",
>> +                               cxt->dev_name, ret);
>> +               goto free_data;
>> +       }
>> +
>> +       pr_info("%s registered as psblk backend\n", cxt->dev_name);
>> +       return;
>> +
>> +free_data:
>> +       kfree(data);
>> +free_stop:
>> +       kfree(stop);
>> +free_cmd:
>> +       kfree(cmd);
>> +free_mrq:
>> +       kfree(mrq);
>> +free_sub:
>> +       kfree(cxt->sub);
>> +out:
>> +       return;
>> +}
>> +
>> +void unregister_mmcpstore(void)
>> +{
>> +       struct mmcpstore_context *cxt = &oops_cxt;
>> +
>> +       unregister_pstore_device(&cxt->dev);
>> +       kfree(cxt->mrq->data);
>> +       kfree(cxt->mrq->stop);
>> +       kfree(cxt->mrq->cmd);
>> +       kfree(cxt->mrq);
>> +       kfree(cxt->sub);
>> +       cxt->card = NULL;
>> +}
>> diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h index
>> 29aa50711626..53840a361b5a 100644
>> --- a/include/linux/mmc/core.h
>> +++ b/include/linux/mmc/core.h
>> @@ -166,6 +166,11 @@ struct mmc_request {
>>
>>  struct mmc_card;
>>
>> +#if IS_ENABLED(CONFIG_MMC_PSTORE)
>> +void mmc_wait_for_pstore_req(struct mmc_host *host, struct
>> +mmc_request *mrq); int mmc_claim_host_async(struct mmc_host *host);
>> +#endif
>> +
>>  void mmc_wait_for_req(struct mmc_host *host, struct mmc_request
>> *mrq);  int mmc_wait_for_cmd(struct mmc_host *host, struct
>mmc_command *cmd,
>>                 int retries);
>> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index
>> c079b932330f..7d6751005ac6 100644
>> --- a/include/linux/mmc/host.h
>> +++ b/include/linux/mmc/host.h
>> @@ -173,6 +173,18 @@ struct mmc_host_ops {
>>          */
>>         int     (*multi_io_quirk)(struct mmc_card *card,
>>                                   unsigned int direction, int
>> blk_size);
>> +
>> +#if IS_ENABLED(CONFIG_MMC_PSTORE)
>> +       /*
>> +        * The following two APIs are introduced to support mmcpstore
>> +        * functionality. Cleanup API to terminate the ongoing and
>> +        * pending requests before a panic write post, and polling API
>> +        * to ensure that write succeeds before the Kernel dies.
>> +        */
>> +       void    (*req_cleanup_pending)(struct mmc_host *host);
>> +       int     (*req_completion_poll)(struct mmc_host *host,
>> +                                       unsigned long timeout); #endif
>>  };
>>
>>  struct mmc_cqe_ops {
>> --
>> 2.17.1
>>

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