From: Christoph Hellwig <hch@lst.de>
To: Ralph Campbell <rcampbell@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>,
John Hubbard <jhubbard@nvidia.com>,
Christoph Hellwig <hch@lst.de>,
Jason Gunthorpe <jgg@mellanox.com>, Shuah Khan <shuah@kernel.org>,
linux-rdma@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org
Subject: Re: [PATCH v4 2/2] mm/hmm/test: add self tests for HMM
Date: Tue, 12 Nov 2019 16:25:21 +0100 [thread overview]
Message-ID: <20191112152521.GC12550@lst.de> (raw)
In-Reply-To: <20191104222141.5173-3-rcampbell@nvidia.com>
Shouldn't this go into mm/ instead? It certainly doesn't seem
like a library.
> +static int dmirror_bounce_copy_from(struct dmirror_bounce *bounce,
> + unsigned long addr)
> +{
> + unsigned long end = addr + bounce->size;
> + char __user *uptr = (void __user *)addr;
> + void *ptr = bounce->ptr;
> +
> + for (; addr < end; addr += PAGE_SIZE, ptr += PAGE_SIZE,
> + uptr += PAGE_SIZE) {
> + int ret;
> +
> + ret = copy_from_user(ptr, uptr, PAGE_SIZE);
> + if (ret)
> + return ret;
> + }
> +
> + return 0;
> +}
Why does this iterate in page sized chunks? I don't remember a page
size limit on copy_{from,to}_user.
> +static int dmirror_invalidate_range_start(struct mmu_notifier *mn,
> + const struct mmu_notifier_range *update)
> +{
> + struct dmirror *dmirror = container_of(mn, struct dmirror, notifier);
> +
> + if (mmu_notifier_range_blockable(update))
> + mutex_lock(&dmirror->mutex);
> + else if (!mutex_trylock(&dmirror->mutex))
> + return -EAGAIN;
> +
> + dmirror_do_update(dmirror, update->start, update->end);
> + mutex_unlock(&dmirror->mutex);
> + return 0;
> +}
Can we adopts this to Jasons new interval tree invalidate?
> +static int dmirror_fops_open(struct inode *inode, struct file *filp)
> +{
> + struct cdev *cdev = inode->i_cdev;
> + struct dmirror_device *mdevice;
> + struct dmirror *dmirror;
> +
> + /* No exclusive opens. */
> + if (filp->f_flags & O_EXCL)
> + return -EINVAL;
Device files usually just ignore O_EXCL, I don't see why this one
would be any different.
> + mdevice = container_of(cdev, struct dmirror_device, cdevice);
> + dmirror = dmirror_new(mdevice);
> + if (!dmirror)
> + return -ENOMEM;
> +
> + /* Only the first open registers the address space. */
> + mutex_lock(&mdevice->devmem_lock);
> + if (filp->private_data)
> + goto err_busy;
> + filp->private_data = dmirror;
> + mutex_unlock(&mdevice->devmem_lock);
->open is only called for the first open of a given file structure..
> +static int dmirror_fops_release(struct inode *inode, struct file *filp)
> +{
> + struct dmirror *dmirror = filp->private_data;
> +
> + if (!dmirror)
> + return 0;
This can't happen if your ->open never returns 0 without setting the
private data.
> + filp->private_data = NULL;
The file is feed afterwards, no need to clear the private data.
next prev parent reply other threads:[~2019-11-12 15:25 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-04 22:21 [PATCH v4 0/2] HMM tests and minor fixes Ralph Campbell
2019-11-04 22:21 ` [PATCH v4 1/2] mm/hmm: make full use of walk_page_range() Ralph Campbell
2019-11-12 15:18 ` Christoph Hellwig
2019-11-12 22:21 ` Ralph Campbell
2019-11-14 14:24 ` Jason Gunthorpe
2019-11-04 22:21 ` [PATCH v4 2/2] mm/hmm/test: add self tests for HMM Ralph Campbell
2019-11-12 15:25 ` Christoph Hellwig [this message]
2019-11-12 21:51 ` Ralph Campbell
2019-11-12 23:45 ` Jason Gunthorpe
2019-11-13 13:51 ` Christoph Hellwig
2019-11-14 23:06 ` Ralph Campbell
2019-11-15 14:06 ` Jason Gunthorpe
2019-11-18 18:32 ` Ralph Campbell
2019-11-18 18:42 ` Jason Gunthorpe
2019-11-13 0:08 ` Andrew Morton
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