Re: [PATCH] bio_integrity_add_page: check for BIO_POOL_NONE beforedetermining nr_vecs on slab

From: David Milburn
Date: Wed Feb 05 2014 - 09:31:55 EST


On 02/03/2014 09:55 PM, Martin K. Petersen wrote:
"David" == David Milburn <dmilburn@xxxxxxxxxx> writes:

David> When enabling DIX T10-DIF-TYPE1-IP protection you can hit the
David> bip_vec full condition which fails to attach the integrity
David> metadata and returns 0 back to bio_integrity_prep()

Looks like Kent accidentally broke this when he changed the bvec pool
setup.

David> - if (bip->bip_vcnt >= bvec_nr_vecs(bip->bip_slab)) {
David> + if (bip->bip_slab != BIO_POOL_NONE &&
David> + bip->bip_vcnt >= bvec_nr_vecs(bip->bip_slab)) {
David> printk(KERN_ERR "%s: bip_vec full\n", __func__);
David> return 0;
David> }

We still need to check that the page will actually fit, though:


block: Fix nr_vecs for inline integrity vectors

Commit 9f060e2231ca changed the way we handle allocations for the
integrity vectors. When the vectors are inline there is no associated
slab and consequently bvec_nr_vecs() returns 0. Ensure that we check
against BIP_INLINE_VECS in that case.

Reported-by: David Milburn <dmilburn@xxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>

diff --git a/fs/bio-integrity.c b/fs/bio-integrity.c
index fc60b31453ee..6dea2b90b4d5 100644
--- a/fs/bio-integrity.c
+++ b/fs/bio-integrity.c
@@ -114,6 +114,14 @@ void bio_integrity_free(struct bio *bio)
}
EXPORT_SYMBOL(bio_integrity_free);

+static inline unsigned int bip_integrity_vecs(struct bio_integrity_payload *bip)
+{
+ if (bip->bip_slab == BIO_POOL_NONE)
+ return BIP_INLINE_VECS;
+
+ return bvec_nr_vecs(bip->bip_slab);
+}
+
/**
* bio_integrity_add_page - Attach integrity metadata
* @bio: bio to update
@@ -129,7 +137,7 @@ int bio_integrity_add_page(struct bio *bio, struct page *page,
struct bio_integrity_payload *bip = bio->bi_integrity;
struct bio_vec *iv;

- if (bip->bip_vcnt >= bvec_nr_vecs(bip->bip_slab)) {
+ if (bip->bip_vcnt >= bip_integrity_vecs(bip)) {
printk(KERN_ERR "%s: bip_vec full\n", __func__);
return 0;
}
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Hi Martin,

Your patch has been tested successfully.

Thanks for your help,
David

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