linux-toradex.git/Documentation/core-api/xarray.rst, branch v5.9-rc5

XArray: Add xa_for_each_range

2020-01-18T03:33:37+00:00

This function supports iterating over a range of an array.  Also add
documentation links for xa_for_each_start().

Signed-off-by: Matthew Wilcox (Oracle)

XArray: Improve documentation of search marks

2019-11-09T04:48:40+00:00

Move most of the mark-related documentation to its own section to make
it easier to understand.  Add clarification that you can't search for
an unset mark, and you can't yet search for combinations of marks.

Signed-off-by: Matthew Wilcox (Oracle)

docs: remove :c:func: annotations from xarray.rst

2019-06-26T17:14:15+00:00

Now that the build system automatically marks up function references, we
don't have to clutter the source files, so take it out.

[Some paragraphs could now benefit from refilling, but that was left out to
avoid obscuring the real changes.]

Acked-by: Matthew Wilcox 
Signed-off-by: Jonathan Corbet

XArray: Use xa_cmpxchg to implement xa_reserve

2019-02-20T22:08:54+00:00

Jason feels this is clearer, and it saves a function and an exported
symbol.

Suggested-by: Jason Gunthorpe 
Signed-off-by: Matthew Wilcox

XArray: Add cyclic allocation

2019-02-06T18:32:25+00:00

This differs slightly from the IDR equivalent in five ways.

1. It can allocate up to UINT_MAX instead of being limited to INT_MAX,
   like xa_alloc().  Also like xa_alloc(), it will write to the 'id'
   pointer before placing the entry in the XArray.
2. The 'next' cursor is allocated separately from the XArray instead
   of being part of the IDR.  This saves memory for all the users which
   do not use the cyclic allocation API and suits some users better.
3. It returns -EBUSY instead of -ENOSPC.
4. It will attempt to wrap back to the minimum value on memory allocation
   failure as well as on an -EBUSY error, assuming that a user would
   rather allocate a small ID than suffer an ID allocation failure.
5. It reports whether it has wrapped, which is important to some users.

Signed-off-by: Matthew Wilcox

XArray: Add support for 1s-based allocation

2019-02-06T18:13:24+00:00

A lot of places want to allocate IDs starting at 1 instead of 0.
While the xa_alloc() API supports this, it's not very efficient if lots
of IDs are allocated, due to having to walk down to the bottom of the
tree to see if ID 1 is available, then all the way over to the next
non-allocated ID.  This method marks ID 0 as being occupied which wastes
one slot in the XArray, but preserves xa_empty() as working.

Signed-off-by: Matthew Wilcox

XArray: Change xa_insert to return -EBUSY

2019-02-06T18:12:15+00:00

Userspace translates EEXIST to "File exists" which isn't a very good
error message for the problem.  "Device or resource busy" is a better
indication of what went wrong.

Signed-off-by: Matthew Wilcox

XArray: Honour reserved entries in xa_insert

2019-01-07T03:12:58+00:00

xa_insert() should treat reserved entries as occupied, not as available.
Also, it should treat requests to insert a NULL pointer as a request
to reserve the slot.  Add xa_insert_bh() and xa_insert_irq() for
completeness.

Signed-off-by: Matthew Wilcox

XArray: Add xa_cmpxchg_irq and xa_cmpxchg_bh

2018-12-06T13:26:17+00:00

These convenience wrappers match the other _irq and _bh wrappers we
already have.  It turns out I'd already open-coded xa_cmpxchg_irq()
in the shmem code, so convert that.

Signed-off-by: Matthew Wilcox

XArray: Fix Documentation

2018-11-05T21:38:10+00:00

Minor fixes.

Signed-off-by: Matthew Wilcox