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Message-ID: <f8de67cb-8d0c-475d-b3f3-bc38ff097823@oracle.com>
Date: Wed, 6 Mar 2024 18:43:13 +0000
From: John Garry <john.g.garry@...cle.com>
To: Xingui Yang <yangxingui@...wei.com>, yanaijie@...wei.com,
jejb@...ux.ibm.com, martin.petersen@...cle.com,
damien.lemoal@...nsource.wdc.com
Cc: linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org,
linuxarm@...wei.com, prime.zeng@...ilicon.com,
chenxiang66@...ilicon.com, kangfenglong@...wei.com
Subject: Re: [PATCH v2] scsi: libsas: Fix disk not being scanned in after
being removed
On 27/02/2024 09:01, Xingui Yang wrote:
> As of commit d8649fc1c5e4 ("scsi: libsas: Do discovery on empty PHY to
> update PHY info"), do discovery will send a new SMP_DISCOVER and update
> phy->phy_change_count. We found that if the disk is reconnected and phy
> change_count changes at this time, the disk scanning process will not be
> triggered.
>
> So update the PHY info with the last query results.
Please mention that sas_unregister_devs_sas_addr() should be called
before sas_set_ex_phy() for this case.
>
> Fixes: d8649fc1c5e4 ("scsi: libsas: Do discovery on empty PHY to update PHY info")
> Signed-off-by: Xingui Yang <yangxingui@...wei.com>
> ---
> v1 -> v2:
> Use sas_get_phy_discover() instead of sas_get_phy_attached_dev() in
> sas_rediscover_dev() and use disc_resp to update phy info.
> ---
> drivers/scsi/libsas/sas_expander.c | 37 ++++++++++++++++++++++--------
> 1 file changed, 28 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
> index a2204674b680..a75dcce7a9ba 100644
> --- a/drivers/scsi/libsas/sas_expander.c
> +++ b/drivers/scsi/libsas/sas_expander.c
> @@ -1940,6 +1940,7 @@ static int sas_rediscover_dev(struct domain_device *dev, int phy_id,
> struct expander_device *ex = &dev->ex_dev;
> struct ex_phy *phy = &ex->ex_phy[phy_id];
> enum sas_device_type type = SAS_PHY_UNUSED;
> + struct smp_disc_resp *disc_resp;
> u8 sas_addr[SAS_ADDR_SIZE];
> char msg[80] = "";
> int res;
> @@ -1951,33 +1952,47 @@ static int sas_rediscover_dev(struct domain_device *dev, int phy_id,
> SAS_ADDR(dev->sas_addr), phy_id, msg);
>
> memset(sas_addr, 0, SAS_ADDR_SIZE);
> - res = sas_get_phy_attached_dev(dev, phy_id, sas_addr, &type);
> + disc_resp = alloc_smp_resp(DISCOVER_RESP_SIZE);
> + if (!disc_resp)
> + return -ENOMEM;
> +
> + res = sas_get_phy_discover(dev, phy_id, disc_resp);
> switch (res) {
> case SMP_RESP_NO_PHY:
> phy->phy_state = PHY_NOT_PRESENT;
> sas_unregister_devs_sas_addr(dev, phy_id, last);
> - return res;
> + goto out;
> case SMP_RESP_PHY_VACANT:
> phy->phy_state = PHY_VACANT;
> sas_unregister_devs_sas_addr(dev, phy_id, last);
> - return res;
> + goto out;
> case SMP_RESP_FUNC_ACC:
> break;
> case -ECOMM:
> break;
> default:
> - return res;
> + goto out;
> + }
> +
> + if (res == 0) {
> + struct discover_resp *dr = &disc_resp->disc;
> +
> + memcpy(sas_addr, dr->attached_sas_addr, SAS_ADDR_SIZE);
> + type = to_dev_type(dr);
> + if (type == 0)
Please use SAS_PHY_UNUSED
> + memset(sas_addr, 0, SAS_ADDR_SIZE);
> }
Any chance we can factor out some of this code with
sas_get_phy_attached_dev() (where it has been copied from)?
>
> if ((SAS_ADDR(sas_addr) == 0) || (res == -ECOMM)) {
> phy->phy_state = PHY_EMPTY;
> sas_unregister_devs_sas_addr(dev, phy_id, last);
> /*
> - * Even though the PHY is empty, for convenience we discover
> - * the PHY to update the PHY info, like negotiated linkrate.
> + * Even though the PHY is empty, for convenience we update
> + * the PHY info, like negotiated linkrate.
> */
> - sas_ex_phy_discover(dev, phy_id);
> - return res;
> + if (res == 0)
> + sas_set_ex_phy(dev, phy_id, disc_resp);
> + goto out;
> } else if (SAS_ADDR(sas_addr) == SAS_ADDR(phy->attached_sas_addr) &&
> dev_type_flutter(type, phy->attached_dev_type)) {
> struct domain_device *ata_dev = sas_ex_to_ata(dev, phy_id);
> @@ -1989,7 +2004,7 @@ static int sas_rediscover_dev(struct domain_device *dev, int phy_id,
> action = ", needs recovery";
> pr_debug("ex %016llx phy%02d broadcast flutter%s\n",
> SAS_ADDR(dev->sas_addr), phy_id, action);
> - return res;
> + goto out;
is there any way to get rid of all the goto's? Ideally we would have
just one location to call kfree(disc_resp)
> }
>
> /* we always have to delete the old device when we went here */
> @@ -1998,7 +2013,11 @@ static int sas_rediscover_dev(struct domain_device *dev, int phy_id,
> SAS_ADDR(phy->attached_sas_addr));
> sas_unregister_devs_sas_addr(dev, phy_id, last);
>
> + kfree(disc_resp);
> return sas_discover_new(dev, phy_id);
> +out:
Calling this simply "out" is odd, as we exit in many places
> + kfree(disc_resp);
> + return res;
> }
>
> /**
As an aside, could libsas - and your changes here - be simpler if we
changed smp_execute_task() like this:
static int smp_execute_task(struct domain_device *dev, void *req /* can
be on the stack */, int req_size,
void *resp /* can be on the stack */, int resp_size)
{
struct scatterlist req_sg;
struct scatterlist resp_sg;
int ret;
void *_req = kmemdup(req, req_size, GFP_KERNEL);
void *_resp = alloc_smp_resp(resp_size);
if (!_req || !resp)
return -ENOMEM;
sg_init_one(&req_sg, _req, req_size);
sg_init_one(&resp_sg, _resp, resp_size);
ret = smp_execute_task_sg(dev, &req_sg, &resp_sg);
memcpy(resp, _resp, resp_size);
kfree(_req);
kfree(_resp);
return ret;
}
We need to use alloc_smp_resp() and alloc_smp_req() as we can't allocate
these memories on the stack for calling sg_init_one(). But if we changed
smp_execute_task() to memcpy from/to data on the stack, it might make
callers simpler. I'm not sure.
Thanks,
John
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