Messages in this thread | | | Date | Sat, 26 Mar 2022 05:19:55 +0200 | Subject | Re: [PATCH v5] mm/hmm/test: use char dev with struct device to get device node | From | Mika Penttilä <> |
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On 25.3.2022 20.17, Jason Gunthorpe wrote: > On Tue, Mar 22, 2022 at 06:35:43AM +0200, mpenttil@redhat.com wrote: >> From: Mika Penttilä <mpenttil@redhat.com> >> >> HMM selftests use an in-kernel pseudo device to emulate device private >> memory. The pseudo device registers a major device range for two pseudo >> device instances. User space has a script that reads /proc/devices in >> order to find the assigned major number, and sends that to mknod(1), >> once for each node. >> >> Change this to properly use cdev and struct device APIs. >> >> Delete the /proc/devices parsing from the user-space test script, now >> that it is unnecessary. >> >> Also, deleted an unused field in struct dmirror_device: devmem. >> >> Signed-off-by: Mika Penttilä <mpenttil@redhat.com> >> Reviewed-by: John Hubbard <jhubbard@nvidia.com> >> Cc: Alistair Popple <apopple@nvidia.com> >> Cc: Ralph Campbell <rcampbell@nvidia.com> >> Cc: Jason Gunthorpe <jgg@ziepe.ca> >> Cc: Vlastimil Babka <vbabka@suse.cz> >> v5: >> - fix whitespace >> . delete unused structure field >> v4: >> - fix commit log >> v3: >> - use cdev_device_add() instead of miscdevice >> v2: >> - Cleanups per review comments from John Hubbard >> - Added Tested-by and Ccs >> >> lib/test_hmm.c | 18 ++++++++++++++---- >> tools/testing/selftests/vm/test_hmm.sh | 6 ------ >> 2 files changed, 14 insertions(+), 10 deletions(-) >> >> diff --git a/lib/test_hmm.c b/lib/test_hmm.c >> index 767538089a62..3c7f2a92b09e 100644 >> +++ b/lib/test_hmm.c >> @@ -29,11 +29,17 @@ >> >> #include "test_hmm_uapi.h" >> >> -#define DMIRROR_NDEVICES 2 >> #define DMIRROR_RANGE_FAULT_TIMEOUT 1000 >> #define DEVMEM_CHUNK_SIZE (256 * 1024 * 1024U) >> #define DEVMEM_CHUNKS_RESERVE 16 >> >> +static const char *dmirror_device_names[] = { >> + "hmm_dmirror0", >> + "hmm_dmirror1" >> +}; >> + >> +#define DMIRROR_NDEVICES ARRAY_SIZE(dmirror_device_names) >> + >> static const struct dev_pagemap_ops dmirror_devmem_ops; >> static const struct mmu_interval_notifier_ops dmirror_min_ops; >> static dev_t dmirror_dev; >> @@ -83,7 +89,7 @@ struct dmirror_chunk { >> */ >> struct dmirror_device { >> struct cdev cdevice; >> - struct hmm_devmem *devmem; >> + struct device device; >> >> unsigned int devmem_capacity; >> unsigned int devmem_count; >> @@ -1225,7 +1231,11 @@ static int dmirror_device_init(struct dmirror_device *mdevice, int id) >> >> cdev_init(&mdevice->cdevice, &dmirror_fops); >> mdevice->cdevice.owner = THIS_MODULE; >> - ret = cdev_add(&mdevice->cdevice, dev, 1); >> + device_initialize(&mdevice->device); >> + dev_set_name(&mdevice->device, "%s", dmirror_device_names[id]); > > Just > dev_set_name(&mdevice->device, "hmm_dmirror%u", id); > > No need for an array
Yeah, no absolute need, thought names in an array is less hardcoded wrt device node count and naming standard.
> > Also check for error
True. Interesting fact is that even the device core itself doesn't check for errors calling dev_set_name(), but sure it can fail in memory allocations.
> > Jason >
Mika
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