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mm/hmm: remove hmm_mirror and related

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The only two users of this are now converted to use mmu_interval_notifier,
delete all the code and update hmm.rst.

Link: https://lore.kernel.org/r/20191112202231.3856-14-jgg@ziepe.ca
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Tested-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
This commit is contained in:
Jason Gunthorpe
2019-11-12 16:22:30 -04:00
parent 81fa1af31b
commit a22dd50640
4 changed files with 32 additions and 538 deletions
Download Patch File Download Diff File Expand all files Collapse all files

183
include/linux/hmm.h
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@@ -68,29 +68,6 @@
#include <linux/completion.h>
#include <linux/mmu_notifier.h>
/*
* struct hmm - HMM per mm struct
*
* @mm: mm struct this HMM struct is bound to
* @lock: lock protecting ranges list
* @ranges: list of range being snapshotted
* @mirrors: list of mirrors for this mm
* @mmu_notifier: mmu notifier to track updates to CPU page table
* @mirrors_sem: read/write semaphore protecting the mirrors list
* @wq: wait queue for user waiting on a range invalidation
* @notifiers: count of active mmu notifiers
*/
struct hmm {
struct mmu_notifier mmu_notifier;
spinlock_t ranges_lock;
struct list_head ranges;
struct list_head mirrors;
struct rw_semaphore mirrors_sem;
wait_queue_head_t wq;
long notifiers;
};
/*
* hmm_pfn_flag_e - HMM flag enums
*
@@ -143,9 +120,8 @@ enum hmm_pfn_value_e {
/*
* struct hmm_range - track invalidation lock on virtual address range
*
* @notifier: an optional mmu_interval_notifier
* @notifier_seq: when notifier is used this is the result of
* mmu_interval_read_begin()
* @notifier: a mmu_interval_notifier that includes the start/end
* @notifier_seq: result of mmu_interval_read_begin()
* @hmm: the core HMM structure this range is active against
* @vma: the vm area struct for the range
* @list: all range lock are on a list
@@ -162,8 +138,6 @@ enum hmm_pfn_value_e {
struct hmm_range {
struct mmu_interval_notifier *notifier;
unsigned long notifier_seq;
struct hmm *hmm;
struct list_head list;
unsigned long start;
unsigned long end;
uint64_t *pfns;
@@ -172,32 +146,8 @@ struct hmm_range {
uint64_t default_flags;
uint64_t pfn_flags_mask;
uint8_t pfn_shift;
bool valid;
};
/*
* hmm_range_wait_until_valid() - wait for range to be valid
* @range: range affected by invalidation to wait on
* @timeout: time out for wait in ms (ie abort wait after that period of time)
* Return: true if the range is valid, false otherwise.
*/
static inline bool hmm_range_wait_until_valid(struct hmm_range *range,
unsigned long timeout)
{
return wait_event_timeout(range->hmm->wq, range->valid,
msecs_to_jiffies(timeout)) != 0;
}
/*
* hmm_range_valid() - test if a range is valid or not
* @range: range
* Return: true if the range is valid, false otherwise.
*/
static inline bool hmm_range_valid(struct hmm_range *range)
{
return range->valid;
}
/*
* hmm_device_entry_to_page() - return struct page pointed to by a device entry
* @range: range use to decode device entry value
@@ -267,111 +217,6 @@ static inline uint64_t hmm_device_entry_from_pfn(const struct hmm_range *range,
range->flags[HMM_PFN_VALID];
}
/*
* Mirroring: how to synchronize device page table with CPU page table.
*
* A device driver that is participating in HMM mirroring must always
* synchronize with CPU page table updates. For this, device drivers can either
* directly use mmu_notifier APIs or they can use the hmm_mirror API. Device
* drivers can decide to register one mirror per device per process, or just
* one mirror per process for a group of devices. The pattern is:
*
* int device_bind_address_space(..., struct mm_struct *mm, ...)
* {
* struct device_address_space *das;
*
* // Device driver specific initialization, and allocation of das
* // which contains an hmm_mirror struct as one of its fields.
* ...
*
* ret = hmm_mirror_register(&das->mirror, mm, &device_mirror_ops);
* if (ret) {
* // Cleanup on error
* return ret;
* }
*
* // Other device driver specific initialization
* ...
* }
*
* Once an hmm_mirror is registered for an address space, the device driver
* will get callbacks through sync_cpu_device_pagetables() operation (see
* hmm_mirror_ops struct).
*
* Device driver must not free the struct containing the hmm_mirror struct
* before calling hmm_mirror_unregister(). The expected usage is to do that when
* the device driver is unbinding from an address space.
*
*
* void device_unbind_address_space(struct device_address_space *das)
* {
* // Device driver specific cleanup
* ...
*
* hmm_mirror_unregister(&das->mirror);
*
* // Other device driver specific cleanup, and now das can be freed
* ...
* }
*/
struct hmm_mirror;
/*
* struct hmm_mirror_ops - HMM mirror device operations callback
*
* @update: callback to update range on a device
*/
struct hmm_mirror_ops {
/* release() - release hmm_mirror
*
* @mirror: pointer to struct hmm_mirror
*
* This is called when the mm_struct is being released. The callback
* must ensure that all access to any pages obtained from this mirror
* is halted before the callback returns. All future access should
* fault.
*/
void (*release)(struct hmm_mirror *mirror);
/* sync_cpu_device_pagetables() - synchronize page tables
*
* @mirror: pointer to struct hmm_mirror
* @update: update information (see struct mmu_notifier_range)
* Return: -EAGAIN if mmu_notifier_range_blockable(update) is false
* and callback needs to block, 0 otherwise.
*
* This callback ultimately originates from mmu_notifiers when the CPU
* page table is updated. The device driver must update its page table
* in response to this callback. The update argument tells what action
* to perform.
*
* The device driver must not return from this callback until the device
* page tables are completely updated (TLBs flushed, etc); this is a
* synchronous call.
*/
int (*sync_cpu_device_pagetables)(
struct hmm_mirror *mirror,
const struct mmu_notifier_range *update);
};
/*
* struct hmm_mirror - mirror struct for a device driver
*
* @hmm: pointer to struct hmm (which is unique per mm_struct)
* @ops: device driver callback for HMM mirror operations
* @list: for list of mirrors of a given mm
*
* Each address space (mm_struct) being mirrored by a device must register one
* instance of an hmm_mirror struct with HMM. HMM will track the list of all
* mirrors for each mm_struct.
*/
struct hmm_mirror {
struct hmm *hmm;
const struct hmm_mirror_ops *ops;
struct list_head list;
};
/*
* Retry fault if non-blocking, drop mmap_sem and return -EAGAIN in that case.
*/
@@ -381,15 +226,9 @@ struct hmm_mirror {
#define HMM_FAULT_SNAPSHOT (1 << 1)
#ifdef CONFIG_HMM_MIRROR
int hmm_mirror_register(struct hmm_mirror *mirror, struct mm_struct *mm);
void hmm_mirror_unregister(struct hmm_mirror *mirror);
/*
* Please see Documentation/vm/hmm.rst for how to use the range API.
*/
int hmm_range_register(struct hmm_range *range, struct hmm_mirror *mirror);
void hmm_range_unregister(struct hmm_range *range);
long hmm_range_fault(struct hmm_range *range, unsigned int flags);
long hmm_range_dma_map(struct hmm_range *range,
@@ -401,24 +240,6 @@ long hmm_range_dma_unmap(struct hmm_range *range,
dma_addr_t *daddrs,
bool dirty);
#else
int hmm_mirror_register(struct hmm_mirror *mirror, struct mm_struct *mm)
{
return -EOPNOTSUPP;
}
void hmm_mirror_unregister(struct hmm_mirror *mirror)
{
}
int hmm_range_register(struct hmm_range *range, struct hmm_mirror *mirror)
{
return -EOPNOTSUPP;
}
void hmm_range_unregister(struct hmm_range *range)
{
}
static inline long hmm_range_fault(struct hmm_range *range, unsigned int flags)
{
return -EOPNOTSUPP;