From: "Margolin, Michael" <mrgolin@amazon.com>
To: Jason Gunthorpe <jgg@nvidia.com>, Leon Romanovsky <leon@kernel.org>
Cc: <linux-rdma@vger.kernel.org>, <sleybo@amazon.com>,
<matua@amazon.com>, <gal.pressman@linux.dev>,
Firas Jahjah <firasj@amazon.com>,
Yonatan Nachum <ynachum@amazon.com>
Subject: Re: [PATCH for-next] RDMA/core: Fix best page size finding when it can cross SG entries
Date: Thu, 13 Feb 2025 16:30:11 +0200 [thread overview]
Message-ID: <777e5518-3f0a-43e8-b80b-0a3ba4ecf5da@amazon.com> (raw)
In-Reply-To: <20250213140421.GZ3754072@nvidia.com>
On 2/13/2025 4:04 PM, Jason Gunthorpe wrote:
> CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you can confirm the sender and know the content is safe.
>
>
>
> On Thu, Feb 13, 2025 at 02:51:26PM +0200, Leon Romanovsky wrote:
>> diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
>> index e7e428369159..63a92d6cfbc2 100644
>> --- a/drivers/infiniband/core/umem.c
>> +++ b/drivers/infiniband/core/umem.c
>> @@ -112,8 +112,7 @@ unsigned long ib_umem_find_best_pgsz(struct ib_umem *umem,
>> /* If the current entry is physically contiguous with the previous
>> * one, no need to take its start addresses into consideration.
>> */
>> - if (curr_base + curr_len != sg_dma_address(sg)) {
>> -
>> + if (curr_base != sg_dma_address(sg) - curr_len) {
>> curr_base = sg_dma_address(sg);
>> curr_len = 0;
> I'm not sure about this, what ensures sg_dma_address() > curr_len?
>
> curr_base + curr_len could also overflow, we've seen that AMD IOMMU
> sometimes uses the very high addresess already
I think the only case we care about where curr_base + curr_len can
overflow is when next sg_dma_address() == 0.
But maybe we should just add an explicit check:
- if (curr_base + curr_len != sg_dma_address(sg)) {
+ if (curr_base + curr_len < curr_base ||
+ curr_base + curr_len != sg_dma_address(sg)) {
curr_base = sg_dma_address(sg);
curr_len = 0;
Michael
next prev parent reply other threads:[~2025-02-13 14:30 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-09 14:26 [PATCH for-next] RDMA/core: Fix best page size finding when it can cross SG entries Michael Margolin
2025-02-13 12:51 ` Leon Romanovsky
2025-02-13 14:04 ` Jason Gunthorpe
2025-02-13 14:30 ` Margolin, Michael [this message]
2025-02-13 14:42 ` Jason Gunthorpe
2025-02-13 17:25 ` Margolin, Michael
2025-02-13 17:35 ` Leon Romanovsky
2025-02-13 17:40 ` Jason Gunthorpe
2025-02-13 17:55 ` Leon Romanovsky
2025-02-13 18:12 ` Jason Gunthorpe
2025-02-14 5:55 ` Leon Romanovsky
2025-02-14 15:33 ` Jason Gunthorpe
2025-02-16 8:07 ` Leon Romanovsky
2025-02-17 8:40 ` Margolin, Michael
2025-02-13 12:53 ` Leon Romanovsky
2025-02-14 6:57 ` Leon Romanovsky
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