Linux-RDMA Archive on lore.kernel.org
 help / color / Atom feed
From: Jason Gunthorpe <jgg@ziepe.ca>
To: Gal Pressman <galpress@amazon.com>
Cc: Doug Ledford <dledford@redhat.com>,
	linux-rdma@vger.kernel.org,
	Alexander Matushevsky <matua@amazon.com>,
	Firas JahJah <firasj@amazon.com>,
	Yossi Leybovich <sleybo@amazon.com>
Subject: Re: [PATCH for-next 6/6] RDMA/efa: Do not delay freeing of DMA pages
Date: Wed, 15 Jan 2020 15:51:04 -0400
Message-ID: <20200115195104.GA929@ziepe.ca> (raw)
In-Reply-To: <20200114085706.82229-7-galpress@amazon.com>

On Tue, Jan 14, 2020 at 10:57:06AM +0200, Gal Pressman wrote:
> When destroying a DMA mmapped object, there is no need to delay the
> pages freeing to dealloc_ucontext as the kernel itself will keep
> reference count for these pages.

Why does the commit message talk about dealloc_ucontext but doesn't
change dealloc_ucontext?

> +	free_pages_exact(cq->cpu_addr, cq->size);
> 	rdma_user_mmap_entry_remove(cq->mmap_entry);

This is out of order, the pages can't be freed until the entry is
removed.

There is also a bug in rdma_user_mmap_entry_remove(),
entry->driver_removed needs to be set while holding the xa_lock or
this is not the required fence.

Jason

  reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-14  8:57 [PATCH for-next 0/6] EFA updates 2020-01-14 Gal Pressman
2020-01-14  8:57 ` [PATCH for-next 1/6] RDMA/efa: Unified getters/setters for device structs bitmask access Gal Pressman
2020-01-15 19:31   ` Jason Gunthorpe
2020-01-16  7:05     ` Gal Pressman
2020-01-14  8:57 ` [PATCH for-next 2/6] RDMA/efa: Properly document the interrupt mask register Gal Pressman
2020-01-14  8:57 ` [PATCH for-next 3/6] RDMA/efa: Device definitions documentation updates Gal Pressman
2020-01-14  8:57 ` [PATCH for-next 4/6] RDMA/efa: Remove {} brackets from single statement if Gal Pressman
2020-01-14  8:57 ` [PATCH for-next 5/6] RDMA/efa: Remove unused ucontext parameter from efa_qp_user_mmap_entries_remove Gal Pressman
2020-01-14  8:57 ` [PATCH for-next 6/6] RDMA/efa: Do not delay freeing of DMA pages Gal Pressman
2020-01-15 19:51   ` Jason Gunthorpe [this message]
2020-01-16  8:26     ` Gal Pressman
2020-01-15 19:58 ` [PATCH for-next 0/6] EFA updates 2020-01-14 Jason Gunthorpe

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200115195104.GA929@ziepe.ca \
    --to=jgg@ziepe.ca \
    --cc=dledford@redhat.com \
    --cc=firasj@amazon.com \
    --cc=galpress@amazon.com \
    --cc=linux-rdma@vger.kernel.org \
    --cc=matua@amazon.com \
    --cc=sleybo@amazon.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-RDMA Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-rdma/0 linux-rdma/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-rdma linux-rdma/ https://lore.kernel.org/linux-rdma \
		linux-rdma@vger.kernel.org
	public-inbox-index linux-rdma

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-rdma


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git